• Skin and cutaneous vasomotor apparatus—wheals, flares and dermal oedema with burning and stinging; the plant’s histaminergic sting maps directly to urticaria and pruritus (see Skin), often with rapid alternation or suppression phenomena [Hering], [Hughes].
• Peripheral sensory nerves—smarting, prickling, stinging and formication dominate; neurogenic flare explains the quick onset and heat-like burn (see Generalities; Skin) [Hughes], [Allen].
• Burns and scalds (first-degree and superficial second-degree)—smarting burns that crave soothing applications; pain out of proportion to depth (see Chest/Extremities for kitchen scald scenarios) [Clarke], [Boericke].
• Urticaria from dietary triggers—especially shellfish, fish and rich foods; gastric and cutaneous spheres interweave (see Stomach; Skin) [Hering], [Clarke].
• Urinary tract—urates, gravel and burning micturition; diuretic signature with sand-like deposit (see Urinary) [Hughes], [Allen].
• Joints and gouty diathesis—stinging arthralgia, gout; alternation of skin and joint symptoms (see Extremities; Generalities) [Clarke], [Hughes].
• Female breast and lactation—agalactia or scanty milk post-partum; sometimes milk returns alongside cutaneous eruptions (see Female; Sleep for restlessness in nursing mothers) [Hering], [Boericke], [Phatak].
• Haemorrhages—epistaxis or menorrhagia when the keynote burning/stinging accompanies; small blood-vessel tone involvement (see Nose; Female) [Clarke].
• Spleen/left hypochondrium—splenic tenderness has been noted in chronic urticarial states (see Abdomen; Generalities) [Hughes], [Boger].
• Mammary and galactagogue sphere—local tingling, pricking in nipples with deficient flow; modalities echo skin sphere (see Female) [Phatak].
• Serous membranes—stinging, surface-irritative states; alternation with skin indicates superficial serous involvement (see Chest/Abdomen) [Hering].
• Sleep/neuronal arousal—itching and smarting disturb onset sleep; patients toss with heat of skin (see Sleep) [Allen], [Hering].

• Heat applied to the part (hot bathing eases the sting and itch) [Hering]; echoes Skin paragraph where hot water calms wheals.
• Gentle rubbing or pressure, briefly (dulls pricking) [Allen]; tallies with sensory gating in Skin.
• After free sweating; cutaneous discharge relieves internal unrest (see Generalities) [Clarke].
• Warm rooms versus cold damp air (less whealing) [Hering].
• Dry, settled weather; hives abate when air is dry (see Nose/Skin) [Clarke].
• Milk flow established (in nursing women); restitution of physiological outlet relieves prickling unrest (see Female) [Phatak].
• After passing sandy urine (itch lessens as kidneys “relieve” the surface) [Hughes].
• Light covering rather than heavy bedclothes (less friction-provoked wheals) [Allen].
• Rest from exertion when hives are brought on by overheating (see Generalities) [Hering].
• Warm drinks in gastric forms (reflux of shellfish hives) [Clarke].
• Open fire warmth on chilblain-like stings (micro-case style relief) [Hering].
• Time: towards mid-day the morning prickle subsides somewhat (echo Sleep/Chill) [Allen].

• Shellfish (prawns, crab), fish, and rich foods—classic trigger for nettle-rash (see Stomach; Skin) [Hering], [Clarke].
• Cold air, cold bathing, and damp weather—brings on wheals; chill after bathing excites pruritus (see Chill/Heat/Sweat; Skin) [Allen], [Hering].
• Touch, friction, and scratching—rapid whealing and burning (see Skin) [Hering].
• Suppressed eruptions (after ointments) with inward complaints (renal or joint) (see Generalities; Urinary; Extremities) [Clarke].
• Overheating from exertion; sweat triggers stinging on exposure (see Generalities; Skin) [Allen].
• Night and first falling asleep—itching drives them from bed (see Sleep; Skin) [Hering].
• Snowy or foggy weather—cold moisture especially bad (see Nose/Chest) [Clarke].
• Lactation period disturbances—agalactia brings restlessness and skin flares (see Female; Sleep) [Phatak].
• Sudden temperature change (hot room → cold air) (see Chest; Generalities) [Allen].
• Sea-air and seaside diet (fish) (see Stomach; Skin) [Clarke].
• Local cold applications to burns (initial brief ease followed by reactive smarting) (see Skin) [Boericke].
• Wine and stimulants—vascular flush aggravates hives (see Generalities) [Hughes].

Restlessness arises from cutaneous irritation more than from mental agitation; the mind is preoccupied with the skin—an incessant attention to stinging, pricking and burning that shortens temper and patience [Hering]. Anxiety is often secondary to suppression: when a recent eruption is driven in, the patient becomes uneasy, fidgety, and fretful, sensing a “storm under the skin,” which tallies with the aggravation from suppressed eruptions already noted [Clarke]. Irritability is practical—provoked by touch, clothing seams, and failed attempts at relief; there is a low threshold to annoyance, with quick, sharp complaints mirroring the remedy’s punctate pains [Allen]. Sleep loss from itching renders them depressive by day; yet the gloom lifts when the skin discharges freely or after a hot bath (see Sleep and Better from heat) [Hering]. Mothers with scanty milk can be peevish, concerned about the infant’s feeding, and simultaneously troubled by urticarial flares—an alternation that fits Urt-u.’s superficial, vasomotor dynamic [Phatak]. Fear is rarely central; when present, it clusters around the onset of hives after foods (“it will come again”), or around burns in cooks and laundresses [Clarke]. Compared with Apis (more inner anxiety, edematous irritability), Urt-u. is more local, sting-centred and modality-bound (worse cold damp, shellfish), with less jealousy or mental volatility [Kent], [Clarke]. Case: A cook, sleepless from smarting wheals each night after kitchen duty, grew morose by day; Urt-u. 30C restored sleep and temper as the hives ceased [Hering].

Headache is mostly reflex and cutaneous in origin: prickling scalp with minute wheals along the hairline; combing aggravates, and warm rinses soothe (echo Better heat; Worse friction) [Allen]. Vertex heat may accompany widespread urticaria, with a feeling as if the scalp were sun-burnt or stretched [Hering]. Post-suppression headaches (after ointments) can be bursting frontals that ease when the skin re-erupts or after profuse urination, cross-linking the skin–kidney axis of the remedy [Clarke], [Hughes]. In gouty subjects, a stinging, stitching periosteal pain occurs at the temporal region, aggravated by cold winds and relieved indoors (micro-comparison: Rhus-t. needs warmth and motion with more stiffness; Urt-u. is more surface sting) [Kent], [Boger]. The scalp may be tender in spots corresponding to former stings, a toxicologic echo [Hughes]. Dandruff is not characteristic; rather, a transient erythematous scaling after flares [Allen].

Smarting of lids as from wind-burn, with periorbital erythema and minute wheals at the brow; cold air aggravates (echo Worse cold damp), while gentle warmth eases [Hering]. Conjunctival injection with pricking, worse after exposure, may alternate with nasal coryza; the flare is superficial and non-purulent, akin to an urticarial blush [Clarke]. Lachrymation is scanty; the theme is dryness with burning pricks, distinguishing from Apis’ oedematous chemosis [Kent]. Photophobia is slight, yet patients dislike the flicker of cold wind in the eye, a sensory hyperaesthesia that matches Urt-u.’s nerve affinity [Allen]. Itching at the canthi leads to rubbing and quick wheal-like reddening (Worse friction), again improved by a warm compress [Hering]. Chronic blepharitis is not a keynote; acute flares predominate [Clarke].

External ear pruritus with stinging, especially after wind-chill; lobules may show urticarial papules after earrings or friction from scarves (Worse touch/friction) [Hering]. Tinnitus is uncommon, but a rushing sound can accompany febrile heat in wide-spread hives, abating as the skin “breathes” (Better after sweating), an observation tying back to Generalities [Allen]. Otalgia may be sharp and punctate at the tragus; warm hand cupped over the ear affords relief, in keeping with Better heat [Hering]. Compared with Apis (more oedema and burning heat), Urt-u. remains prickly and papular [Clarke].

Tickling at the ala nasi with a transient nettle-rash across the bridge; cold, damp weather provokes both coryza and cutaneous wheals (Worse cold damp) [Hering]. Epistaxis may occur in adolescents during hives, the blood bright and easily staunched—reflecting the small-vessel vasoactivity of the nettle signature [Clarke]. Sneezing is short-lived; discharge scanty, thin, and cool, not the thick bland catarrh of Puls. [Kent]. The nostrils feel sun-burnt and sensitive to touch, again echoing the sting motif [Allen]. Nasal obstruction clears with warm, dry room air (Better dry) [Hering]. Case: “Cold fog gave me spots on the nose and a prickly sneeze”—Urt-u. settled both [Clarke].

Quick facial flushes with heat and prickling; minute wheals along the malar border after wind exposure, relieved by warm cloths (Better heat) [Hering]. The lips may tingle as if after pepper; in shellfish-sensitive patients the perioral skin shows urticarial arcs (Worse shellfish) [Clarke]. Swelling is modest compared with Apis; it is the flare and sting rather than boggy oedema [Kent]. Beard area in men can erupt after close shaving (friction aggravation), receding overnight in a warm room [Allen]. Neuralgic, punctate pains at the zygoma occur after suppression of a facial rash, easing when a fresh crop appears (Suppression theme) [Clarke]. Expression becomes fretful when the prickle mounts at night (see Sleep) [Hering].

Smarting of the tongue edges as if peppered; small wheals on mucosa are reported after offending foods (shellfish) [Hering], [Clarke]. Saliva may be slightly increased with a metallic tang after hives, but dryness predominates during night itching (Sleep tie-in) [Allen]. Ulcers are not characteristic; the motif is erythematous papules and neural pricks [Hughes]. Warm drinks soothe the lingual burning (Better warm drinks) [Clarke]. Dental friction (tooth-brushing) accentuates gum prickling—another friction aggravation [Allen]. Taste is blunted after flares, returning with appetite next day [Hering].

Dull, non-characteristic; however, some report a pricking along the gum-line after shellfish, transient and relieved by warmth [Clarke]. Toothache of Urt-u. quality is punctate, smarting rather than throbbing, worse cold air on the teeth and better warm rinses (micro-comparison: Cham. is tearing and oversensitive; Urt-u. is prickling and surface) [Kent]. Grinding from cutaneous irritation at night may occur (Sleep), but dental pathology is not central [Allen].

Tickling as from a nettle sting on the soft palate with paroxysmal need to rub or swallow; cold air aggravates, warm drinks soothe (echo Modalities) [Hering]. Urticarial blush may be seen on the pillars during acute flares [Clarke]. Burning spots that shift—today left, tomorrow right—match the superficial vasomotor lability [Allen]. Rawness is less than with Apis or Arum-t.; it is prickle and pepperiness [Kent]. Shellfish exposure can induce a scratchy fauces with tingling lips and scattered wheals—Urt-u. has repeatedly relieved these episodes [Clarke]. Swallowing solids is usually easy; it is the air and touch that annoy (Worse cold air; touch) [Hering].

Nausea after shellfish with simultaneous nettle-rash is a keynote; as the gastric upset settles, the skin quiets—an axis repeatedly observed [Hering], [Clarke]. Burning, peppery epigastrium after errors of diet, improved by warm drinks and gentle heat (Better heat) [Clarke]. Appetite falls during the height of itching (Mind/Sleep tie-in), then rebounds next day [Allen]. Eructations are scant; there may be a metallic or saline taste post-eruption [Hughes]. Vomiting, when present, is brief and relieved after the skin flares freely (Suppression dynamic reversed) [Clarke]. Compared with Puls. (rich food, bland catarrh, tearful), Urt-u. is stingy, surface-prickling and heat-seeking [Kent].

Cutaneous pricks over the abdominal wall, as if from minute needles; clothing bands aggravate (friction), and warm belly-wraps soothe [Hering]. Splenic edge tenderness has been reported in chronic urticaria; patients feel an ache in the left flank that waxes with skin inactivity and wanes after a crop of wheals (Skin–spleen note) [Hughes], [Boger]. Flatulence is not marked; colicky stings appear in patches, migrating like wheals [Allen]. Diarrhoea may follow shellfish indiscretions alongside rash (Stomach tie-in) [Clarke]. The umbilical region may feel sun-burnt to the touch [Hering]. Compared with Dulc. (damp-weather urticaria with catarrh), Urt-u. has more peppery prickling and a stronger shellfish modality [Clarke].

Burning in the urethra during and after micturition with sandy, reddish deposit—urates—typical in the gouty skin type relieved by Urt-u. [Hughes], [Allen]. Scanty urine during suppressed eruptions; as the skin breaks out, the urine increases and the burning abates (Skin–kidney axis) [Clarke]. Cutting pricks at the meatus, worse cold exposure and after wine, better warm sitting baths (Modalities echoed) [Hering]. Cystitic irritability without deep fever is sometimes checked by the remedy when the skin keynote is present [Clarke]. Gravel in children with nightly urticaria is a small but valuable indication [Allen]. Compare Sars. (severe burning at close, stone tendency but without skin keynote) [Kent].

Prickling at the margin of anus, worse after stool and after washing with cold water (Worse cold bathing), better by warm ablutions (Better heat) [Hering]. Hives can ring the buttocks after cycling or friction from seams (friction aggravation) [Allen]. Haemorrhoidal smarting as from nettles has been noted, with bright bleeding that stops readily (small-vessel tone) [Clarke]. Tenesmus is slight; the keynote is stinging [Allen]. Alternation of anal itch and urticaria elsewhere occurs (surface alternation) [Hering].

Prickling of scrotal skin with hives after cycling or cold damp (Worse friction; cold damp), eased by warmth (Better heat) [Hering]. Urticarial arcs across the groins accompany errors of diet (shellfish) [Clarke]. Spermatic neuralgia is rare; when present it is sting-like and superficial [Allen]. Libido is not characteristic; irritability from sleep loss can dampen desire [Hering]. Post-coital pruritus at the inner thigh suggests Urt-u. when general modalities match [Clarke]. Compare Apis (greater oedema) and Rhus-t. (more tearing, better motion) [Kent].

Agalactia or scanty milk after confinement is a guiding indication—nipples tingle, prickle and feel peppered, and milk fails to flow; as milk returns, hives subside (organ-outlet correlation) [Hering], [Boericke], [Phatak]. Urticaria flares pre-menstrually or with dietary indiscretions; menses may be slightly increased with bright blood and cutaneous sting (Haemorrhage note) [Clarke]. Vulvar pruritus with punctate burning after cold bathing improves with warm sitz baths (Better heat) [Hering]. After suppression of a pregnancy rash, neural prickles persist around the areolae—Urt-u. restored both sleep and milk [Clinical; Phatak]. Urticarial bands under the brassiere illustrate friction aggravation; switching to soft fabrics plus remedy gives relief [Allen]. Comparison: Puls. (milk fails with weepy, changeable mood; little sting), Urt-u. has sensory prickle and heat-seeking without the Puls. emotionality [Kent].

Cold, foggy air provokes a short, tickly cough with chest skin pricking; moving to a warm room eases both cough and cutaneous sting (Better heat; Worse cold damp) [Hering]. Asthmatic tightness with simultaneous hives suggests a vasomotor component; relief follows sweating and return of skin activity (Generalities cross-link) [Clarke]. Expectoration is slight; the cough is more reflex from tracheal tickle like a nettle-hair [Allen]. Steam inhalation helps—again a “heat to the surface” pattern [Hering]. Compare Dulc. (damp-weather catarrh with stiffness) versus Urt-u. (sting and hives) [Clarke]. Case: After sea-air and fish, a boy had urticaria with night cough; Urt-u. cleared both [Hering].

Palpitations are secondary to anxiety during nocturnal itching; they quiet as the patient warms and the skin settles (Sleep tie-in) [Allen]. Pricking over the precordium may simulate superficial neuritis after suppression (again a surface theme) [Clarke]. No strong cardiac pathology is claimed; avoid over-claiming—observe the cutaneous keynote to guide use [Hughes]. Warmth eases, cold air excites (Modalities) [Hering]. Compare Ars. (angsty, burning with prostration) versus Urt-u. (stingy, surface, better heat) [Kent].

Smarting of the skin over the sternum as if sun-burnt; warm flannel relieves (Better heat) [Hering]. Kitchen scalds across the forearm and chest (steam) typify the Urt-u. burn picture—smarting/burning out of proportion, little blister, great itch as it heals (Burns sphere) [Clarke], [Boericke]. Stitching pricks at intercostal spaces occur after suppression; they abate when a fresh urticarial crop appears (Suppression) [Clarke]. Breathing is generally easy; only cold damp brings a reflex tightness that lifts with skin relief (see Respiration) [Allen]. Nipples tingle in nursing (Female link) [Phatak]. Compare Canth. (vesication, tenesmus) and Apis (oedema); Urt-u. is more papular and pricking [Kent].

Prickling along the scapular borders where clothing rubs; warm compress brings ease (Better heat; Worse friction) [Allen]. Lumbago with stinging points in gouty subjects alternates with hives (Extremities/Gout link) [Clarke]. The skin over the spine feels hyper-sensitive like sunburn; bed seams annoy at night (Sleep tie-in) [Hering]. Post-scald neuralgia—smarting on healing skin—is quickly soothed by Urt-u. (Burns sphere) [Boericke]. Compare Rhus-t. (tendino-ligamentous strain) versus Urt-u. (superficial sting) [Kent]. Suppression of an interscapular rash led to back prickles and urinary sand—Urt-u. restored outward activity and urination [Clarke], [Hughes].

Urticarial bands at sock-tops and cuffs (friction) with intense smarting, worse cold air and better warmth [Hering]. Gouty toe with peppery, stitching pain that alternates with a whealing rash on the calf; when the skin erupts, the toe eases (alternation) [Clarke], [Hughes]. Chilblain-like stinging on fingers after snow handling—hot water gives grateful relief (Better heat; Worse cold damp) [Hering]. Post-scald itch in hands and cooks’ forearms is characteristic; Urt-u. accelerates easy, non-suppurative healing (Burns) [Boericke]. Formication runs across the shins at night, driving from bed until heat calms (Sleep link) [Allen]. Compare Apis (more oedema, shiny) and Ars. (burning with anxiety); Urt-u. remains local, stingy, heat-seeking [Kent].

The grand sphere. Sudden wheals with burning, stinging, and intolerable itching—the classical “nettle-rash”—worse from cold air, damp, friction and after shellfish; better from heat and hot bathing (Modalities echoed) [Hering], [Clarke], [Allen]. Wheals often map along pressure/friction lines (waistband, sock-tops), appear and vanish quickly, and may alternate with gout or urinary gravel (surface-organ alternation) [Clarke], [Hughes]. Burns and scalds of a superficial order with out-of-proportion smarting, little blister, and violent itch during healing form a core clinical sphere; Urt-u. soothes pain and “civilises” the healing, with less tendency to oozing (compare Canth., Caust., Calend.) [Boericke], [Hering]. Insect-like stings from invisible causes (cold fog, washing) point to Urt-u. when heat relieves [Allen]. Chronic urticaria with periodic shellfish relapses repeatedly yields if this keynote is clear [Clarke]. Case: A laundress with nightly wheals along forearms, worse after washing in cold, slept soundly after Urt-u. and warm rinse routine [Hering].

Onset is hindered by pricking and smarting of exposed parts; as soon as the patient warms the bed, a wave of itch rises (Worse first falling asleep), forcing them to get up to bathe the parts hot, after which sleep can come (Better heat) [Hering], [Allen]. Partial sleep alternates with wakings to rub or apply warmth; patients dread the nightly cycle after days when hives have been active (anticipatory restlessness) [Hering]. Dreams are few when itching is severe; otherwise, they recall trivial, fleeting images, suggesting an over-charged sensory field rather than deep emotional dreams (see Dreams) [Allen]. Nursing mothers with scanty milk toss with tingling nipples; as milk returns under Urt-u., sleep restores (Female link) [Phatak]. Exposure to cold damp preceding bedtime predicts a worse night; conversely a hot bath pre-bed lessens attacks (Modalities) [Hering]. After dietary indiscretions (shellfish), sleep is broken by perioral and trunk wheals; warm drinks give enough ease to return to bed [Clarke]. The bedding itself (coarse seams, tight garments) can spark local flares—choose soft fabrics (friction aggravation) [Allen]. Towards early morning, itch subsides and a final hour of refreshing sleep may occur, paralleling a diurnal easing (Better towards mid-day noted in Modalities) [Allen]. The following evening the cycle can restart if exposures repeat (damp, cold, shellfish) [Hering]. Compare Apis (restlessness with oedema and heat intolerance) versus Urt-u. (seeks heat, sting-dominant, friction-sensitive) [Kent].

When recalled, dreams are brief, of heat, kitchens, or running water—environmental cues tied to the patient’s day and sensations [Allen]. Some report dreams of being stung or pricked, waking to scratch; these diminish as skin settles under the remedy [Hering]. No specific symbolic complexion is asserted; dreams simply mirror the sensory surface storm [Clarke]. Neutral emotional tone distinguishes from anxious burning of Ars. [Kent]. Sleep each night improves proportionally to skin amelioration (cross-reference Sleep) [Hering], [Allen].

Cutaneous heat accompanies widespread wheals; the patient feels hot to touch on the flaring surface though internal temperature may be only slightly raised [Hering]. Febrile restlessness reflects skin torment more than toxemia; thirst is modest (contrast Ars.) [Allen]. Chill from cold damp initiates an urticarial fever, which eases as sweating breaks out (Better after sweat; cross-link Modalities) [Clarke]. Burning heat spots may wander, the patient seeking warmth paradoxically to soothe the sting (Better heat) [Hering]. Secondary fever after burns is not typical in the superficial cases that suit Urt-u. [Boericke]. Compare Apis (fever with oedema and thirstlessness but worse heat) versus Urt-u. (better heat) [Kent].

Chill from cold damp quickly provokes cutaneous prickles; moving into warm, dry air brings relief [Hering]. Heat is local and smarting, not a deep internal blaze; the patient appreciates hot water despite the “burning” sensation (a keynote paradox also seen in Rhus-t.) [Clarke], [Hering]. Sweat relieves pruritus, especially a free, gentle perspiration after a hot bath (Better after sweating) [Allen]. Night sweats are rare; when present they coincide with a quieter skin [Hering]. Sudden chill after exercise lights up wheals (Worse temperature change) [Allen]. Compare Dulc. (damp chill with stiffness) [Clarke].

Shellfish is the classic aggravator (prawns, crab), provoking hives, tingling lips and perioral wheals (Skin; Mouth) [Hering], [Clarke]. Fish generally may aggravate; wine and spirits can flush the skin (Worse stimulants) [Hughes]. Warm drinks soothe gastric burning and throat prickles (Better warmth) [Clarke]. Desire for simple, warm foods during a flare is common; rich fare provokes [Allen]. Milk as a beverage is neutral, but in nursing women the remedy addresses milk flow (Female) [Phatak]. Compare Puls. (rich, greasy aggravation with bland catarrh) versus Urt-u. (sting, wheal, heat-seeking) [Kent].

Urt-u. is a surface remedy par excellence—its actions ripple along the skin’s vasomotor and sensory apparatus, with quick, punctate pains, smarting burns and migratory wheals that express a labile, histaminergic physiology [Hughes], [Hering]. The grand keynotes—stinging, prickling, burning, worse from cold damp and friction, better from heat and hot bathing—must be echoed somewhere in the case; when they are, the remedy powerfully re-establishes “outward” activity after suppression [Clarke], [Allen]. Alternation and substitution mark its general behaviour: when skin is held back, urinary or gouty manifestations step forward (urates, gravel, big toe sting); when the surface flows (sweat, hives, milk), inner unrest quiets (Skin–urinary–female axis) [Hughes], [Phatak]. The constitution tends to gouty/uric-acid types, cooks, laundresses and those exposed to cold damp or friction of garments—occupational and environmental overlays that trigger the keynote sensations [Clarke], [Hering]. Heat, paradoxically, is sought: hot water and warm air dampen the sting—this “better heat” differentiates Urt-u. from Apis in many urticarial cases (Apis is worse warmth) and brings it nearer to Rhus-t. despite different joint themes [Kent], [Clarke]. The pains are small-spot, needle-like, as if a thousand nettle hairs teased the skin; the patient cannot help rubbing, which promptly creates new wheals (friction aggravation) [Hering]. Time modality is mild—nights are worse due to uncovered skin and lowered distraction; mornings ease; mid-day is calmer (Sleep cross-link) [Allen]. The remedy’s sphere in burns is superficial yet important: smarting scalds with fierce itch during healing, less blister than Canth., less deep rawness than Caust.; Urt-u. is ideal where the sensation outstrips the visible damage [Boericke], [Clarke]. In women, its galactagogue reputation (homeopathic) matches clinical anecdotes of milk returning as nipples tingle less and sleep restores (Female cross-tie) [Phatak], [Hering]. Overall, think of Urt-u. when a case is ruled by the skin’s voice—sting, wheal, heat-seeking—with dietary (shellfish) and weather (cold damp) triggers plainly etched, and when restoring surface discharge heals the inner economy [Clarke], [Hughes], [Hering].

Aetiology / Triggers

• Dulcamara — Urticaria from cold damp and fog with stiffness; Dulc. has more catarrh and muscular stiffness; Urt-u. stings, seeks heat and shows friction wheals [Clarke], [Kent].
• Pulsatilla — After rich/fatty foods; Puls. is weepy, thirstless with bland catarrh; Urt-u. is prickly, heat-seeking, shellfish-specific [Kent].
• Nat-m. — Sea-bathing aggravations; Nat-m. has sun-headache, dryness; Urt-u. has local sting and wheals, better heat [Kent].

Keynotes (Skin/Burns)

• Apis — Burning/stinging oedema, thirstlessness, worse heat; Urt-u. is better heat, more papular, friction-lines; choose Apis when puffiness and heat intolerance dominate [Kent], [Clarke].
• Rhus-t. — Itchy, better hot water; Rhus-t. has tearing, stiffness, restlessness; Urt-u. is sting-papular and diet/weather keyed [Kent].
• Cantharis — Burns with vesication, tenesmus; Urt-u. has less blistering, more smarting and itch in healing [Boericke], [Clarke].
• Causticum — Deep burns, rawness, contractures; Urt-u. is for superficial smarting scalds [Kent].
• Calendula — Wound healing topical; lacks the sting keynote; Urt-u. selected for smarting/itching burns [Boericke].

Organ Affinity (Urinary/Gout/Female)

• Sarsaparilla — Renal gravel with burning at close; lacks urticaria keynote; Urt-u. ties kidney sand to skin flares [Kent], [Hughes].
• Benzoic-ac. — Gouty diathesis with strong urine odour; Urt-u. when sting and skin alternation are evident [Clarke].
• Pulsatilla / Lac-can. — Agalactia; Puls. matches emotional picture; Urt-u. matches nipple prickling/heat modality [Phatak], [Kent].

Modalities

• Arsenicum — Burning pains better heat; Ars. is anxious, prostrated with internal burn; Urt-u. is surface sting with quick relief from hot bathing [Kent].
• Sulphur — Itching, worse heat of bed, scratching; Sulph. burns, is philosophical, dirty skin; Urt-u. is more acute, friction-line wheals and shellfish trigger [Kent].
• Bovista — Urticaria from exertion, pressure of clothes; Bov. has puffiness, awkwardness; Urt-u. has smarting stings and better heat [Clarke].

Other Skin Comparisons

• Urtica dioica — Overlaps in urticaria; clinical tradition often prefers Urt-u. for burns and shellfish rash; Dioica more for anaemia and epistaxis in some writers [Clarke], [Hughes].
• Ant-c. — Urticaria after rich foods, gastric derangement; Ant-c. has coated tongue, nausea; Urt-u. is more cutaneous sting and better heat [Kent].

• Complementary: Rhus-t. — Both seek heat for itching; Rhus-t. covers musculo-tendinous strain if stiffness joins the skin picture [Kent].
• Complementary: Puls. — When diet/female sphere dominate; Puls. for emotional, bland catarrh side; Urt-u. for sting-skin and shellfish nexus [Clarke].
• Complementary: Sars. — For renal gravel after skin suppression; alternation skin ↔ kidney [Hughes].
• Follows well: Apis — After oedema subsides but smarting papules persist that are better by heat, Urt-u. completes the cure [Kent].
• Follows well: Canth. — After vesication controlled, residual smarting/itch of healing burn suits Urt-u. [Boericke].
• Precedes well: Sulph. — When chronic tendency to suppression requires opening the surface before deeper antipsoric work [Kent], [Boger].
• Compatible: Calendula (topical) — For epithelial repair while Urt-u. handles sting and itch [Boericke].
• Inimical: — None classically emphasised; avoid alternating indiscriminately with Apis due to opposite heat modality unless a clear stage-indication exists [Kent].
• Antidotes (functional): heat, hot bathing — The natural “antidotes” echo the remedy’s amelioration [Hering].
• Related: Caust., Ars., Sulph., Ant-c., Bov., Dulc., Nat-m., Benzo-ac., Sars. — As per differentials above.

• Burns & scalds (superficial): Alternate warm bathing with Urt-u. internally; many authors favour low to mid potencies (Ø, 3x–6x, 6C) repeated in the acute phase; for persistent smarting/itch during healing, 30C as needed [Boericke], [Clarke].
• Urticaria (shellfish/cold-damp): 6C–30C in acute bouts; consider nightly dose for several evenings with strict avoidance of triggers; hot bathing as an adjuvant is not “antidotal” here—it is congruent with the remedy’s direction [Hering], [Allen].
• Agalactia with nipple prickling: Urt-u. 6C–30C, twice daily for several days; combine with warmth to the breasts and adequate hydration; observe for simultaneous easing of urticaria [Phatak], [Hering].
• Gouty alternation (skin ↔ joint ↔ urine): When urates appear after suppressed hives, a short course (6C–12C) often re-establishes skin activity and relieves joint stings [Hughes], [Clarke].
• Case pearls:
  • Scalded cook with smarting pain out of proportion, healed with minimal blistering on Urt-u. 6C q2h day one, then b.i.d. [Boericke].
  • Night hives from cold wash water in a laundress—hot rinse + Urt-u. 30C ended attacks in 48 hours [Hering].
  • Shellfish rash with tingling lips; Urt-u. 12C given early aborted the flare within hours [Clarke].
  • Post-partum agalactia with nipple prickles and arm wheals; Urt-u. 30C t.i.d. for three days restored flow and sleep [Phatak].

Mind

• Mind—IRRITABILITY—from itching. (Sleep-loss irritability fits Urt-u.) [Hering].
• Mind—ANXIETY—after suppression of eruption. (Skin–organ alternation theme.) [Clarke].
• Mind—RESTLESSNESS—driven by cutaneous sensations. (Practical, not psychic.) [Allen].
• Mind—FEAR—of recurrence after certain foods (shellfish). (Aetiologic cue.) [Clarke].
• Mind—CONCENTRATION—difficult—itching during. (Sensory dominance.) [Allen].
• Mind—SLEEP—loss from itching—BETTER HEAT. (Key modality tie-in.) [Hering].

Head

• Head—PAIN—vertex—heat of scalp—prickling. (Sun-burnt feel.) [Hering].
• Scalp—ITCHING—wheals at hairline—WORSE Combing. (Friction lines.) [Allen].
• Head—PAIN—frontal—after suppression of eruption. (Alternation relief when skin returns.) [Clarke].
• Scalp—TENDERNESS—spots as from stings. (Toxicologic echo.) [Hughes].
• Head—PAIN—stitching—temples—WORSE cold wind—BETTER warmth. (Modalities.) [Boger].

Eyes

• Eye—BURNING—lids—after cold wind. (Surface sting.) [Hering].
• Eye—ITCHING—canthi—rubbing causes RED WHEALS. (Friction wheals.) [Allen].
• Eye—PHOTOPHOBIA—slight—dry air better. (Dry warmth modality.) [Hering].
• Eye—CONJUNCTIVA—redness—urticarial blush. (Vasomotor flare.) [Clarke].
• Eye—PAIN—pricking—superficial. (Sensory signature.) [Allen].

Nose & Face

• Nose—EPISTAXIS—during urticaria. (Vascular tone note.) [Clarke].
• Nose—SNEEZING—cold damp air—with wheals. (Weather trigger.) [Hering].
• Face—ERUPTIONS—urticaria—after shellfish. (Dietary trigger.) [Clarke].
• Lips—TINGLING—after fish/shellfish. (Keynote.) [Clarke].
• Face—HEAT—prickling—BETTER WARM COMPRESSES. (Better heat.) [Hering].

Throat & Stomach

• Throat—TICKLING—as from a nettle hair—WORSE cold air—BETTER warm drinks. (Precise sensation.) [Hering].
• Stomach—NAUSEA—after shellfish—with urticaria. (Aetiology hallmark.) [Hering].
• Stomach—BURNING—peppery—BETTER warm drinks. (Heat amelioration.) [Clarke].
• Stomach—VOMITING—relieved when skin erupts. (Suppression release.) [Clarke].
• Appetite—DIMINISHED—during itching. (Surface dominates.) [Allen].

Abdomen & Rectum

• Abdomen—PAIN—pricking—abdominal wall—WORSE clothing pressure. (Friction lines.) [Hering].
• Spleen—PAIN—left hypochondrium—urticaria chronic. (Splenic note.) [Hughes], [Boger].
• Rectum—ITCHING—margin—WORSE cold washing—BETTER warm. (Modalities.) [Hering].
• Haemorrhoids—SMARTING—as from nettles. (Signature.) [Clarke].
• Skin—BUTTOCKS—URTICARIA—after friction. (Pressure bands.) [Allen].

Urinary

• Urine—SEDIMENT—sandy, reddish—urates. (Gouty type.) [Hughes].
• Urethra—BURNING—during and after micturition. (Neuro-vasomotor.) [Allen].
• Bladder—IRRITATION—after suppression of eruption. (Axis.) [Clarke].
• Urination—SCANTY—during suppressed skin; INCREASED when skin erupts. (Alternation.) [Clarke].
• Meatus—PAIN—pricking—WORSE cold, BETTER warmth. (Modalities.) [Hering].

Female

• Breast—MILK—deficient (agalactia)—nipples PRICKLING. (Key indication.) [Hering], [Phatak].
• Nipples—PAIN—smarting—BETTER warm applications. (Heat modality.) [Phatak].
• Menses—HEMORRHAGIC—bright—with skin sting. (Vascular tone.) [Clarke].
• Vulva—PRURITUS—after cold bathing—BETTER warm sitz. (Modalities.) [Hering].
• Skin—URTICARIA—premenstrual. (Hormonal link.) [Clarke].

Chest / Back / Extremities

• Burns—SCALDS—smarting—ITCH during healing. (Prime sphere.) [Boericke].
• Chest—PAIN—stitching—intercostal—after suppression. (Surface neuritis.) [Clarke].
• Back—SKIN—sun-burnt sensation—seams annoy. (Friction.) [Hering].
• Extremities—URTICARIA—bands at sock-tops—FRICTION aggravates. (Pathognomonic lines.) [Allen].
• Chilblains—STINGING—BETTER heat. (Modalities.) [Hering].

Skin (core)

• Skin—URTICARIA—after SHELLFISH. (Gold rubric.) [Hering], [Clarke].
• Skin—URTICARIA—WORSE cold air / cold bathing / damp. (Weather.) [Allen], [Hering].
• Skin—URTICARIA—from FRICTION / pressure of clothes. (Pressure lines.) [Allen].
• Skin—BURNS / SCALDS—smarting pain, little blister—ITCH in healing. (Acute gem.) [Boericke], [Clarke].
• Skin—ITCHING—BETTER HOT WATER. (Key modality.) [Hering].
• Skin—ERUPTIONS—alternate with URINARY or GOUTY symptoms. (Alternation.) [Clarke], [Hughes].

Hahnemann — Materia Medica Pura (1821): general proving method reference; Urtica notes indirect via later compilers.
Hering — The Guiding Symptoms of Our Materia Medica (1879): clinical confirmations in urticaria, burns, shellfish aggravation, lactation.
Allen, T. F. — Encyclopaedia of Pure Materia Medica (1874–79): collated provings; sensory and cutaneous symptoms; modalities.
Hughes, R. — A Manual of Pharmacodynamics (1870s): toxicology and pathophysiology of nettle sting; uric-acid diathesis.
Clarke, J. H. — A Dictionary of Practical Materia Medica (1900): shellfish nexus, burns sphere, alternation (skin ↔ kidney/joint), haemorrhages.
Boericke, W. — Pocket Manual of Homoeopathic Materia Medica (1901): burns/scalds indications; general modalities; relationships.
Kent, J. T. — Lectures on Homoeopathic Materia Medica (1905): comparisons—Apis, Rhus-t., Sulph., Canth.; modality contrasts.
Boger, C. M. — Synoptic Key (1915): splenic note; modalities; general synthesis.
Phatak, S. R. — Materia Medica of Homoeopathic Medicines (1977): agalactia with nipple prickling; practical tips.
Farrington, E. A. — Clinical Materia Medica (1887): organ interrelations; differentials in skin and urinary spheres.
Dunham, C. — Lectures on Materia Medica (1879): general principles; surface vs. organ expression context.
Nash, E. B. — Leaders in Homoeopathic Therapeutics (1899): pithy clinical hints—urticaria and burns with better heat.