Aquagenic urticaria: diagnostic and management challenges

Figures & data

Table 1 Differential diagnosis of aquagenic urticaria

Differential diagnosis	Distinguishing features	Diagnostic testing
Aquagenic urticaria	Distinguish from evaporative cooling and cold urticaria	Wet cloth at room temperature applied for 20 minutes
Salt-dependent aquagenic urticaria	Sea water provokes lesions, with or without symptoms from tap or distilled water	3.5% NaCl at room temperature soaked in wet cloth applied for 20 minutes
Aquagenic pruritus	Pruritus without the appearance of skin lesions	Wet cloth at room temperature applied for 20 minutes
Dermatographism	Linear, pruritic hives from shear force, the most common physical urticaria	Linear stroking at various pressures (20–144 g/m^2) using dermatographometer, Fric test, or ballpoint pen
Cholinergic urticaria	Pinpoint diffuse papular lesions from increase in internal core body temperature	Exercise challenge to induce sweat for >10 minutes or passive warming using hot water bath to raise body temperature >1°C
Cold urticaria	Pruritic wheal and flare from cold contact, up to one-third of cases of physical urticaria	Placement of ice water in 50 mL beaker for 1–10 minutes, cold hand immersion for 5 minutes, total body cold exposure, evaporative cooling
Delayed pressure urticaria	Pruritus, swelling, and pain 4–8 hours after exposure may be associated with systemic symptoms of fatigue and arthralgia	100 g/m^2 of pressure for 5–180 seconds on the forearm using a dermatographometer or 15 lb weight bearing on the shoulder or the lower leg for 15–20 minutes
Exercise-induced urticaria	Not induced by passive warming, larger lesions often associated with systemic symptoms	Exercise challenge as above
Local heat urticaria	Reaction limited to area of exposure	Placement of hot water (45°C–50°C) in beaker for 1–10 minutes
Solar urticaria	Immediate reaction to UV and visible light, resolves within 24 hours, distinguish from polymorphous light eruption	UVA, UVB, and visible light stimulation of variable intensity to establish minimal urticarial dose
Vibratory angioedema	Erythema and swelling beyond provocation site	Vortex vibratory stimulation for 4 minutes at 2,500 rpm

Note: Adapted from Komarow HD, Arceo S, Young M, Nelson C, Metcalfe DD. Dissociation between history and challenge in patients with physical urticaria. J Allergy Clin Immunol Pract. 2014;2(6):786–790. Copyright 2014, with permission from Elsevier.¹⁸

Abbreviation: UV, ultraviolet.

Table 2 Therapeutic options for aquagenic urticaria

Therapeutic options	Line of therapy/notes	Proposed mechanism
Nonsedating, second-generation H1 antihistamines (eg, cetirizine)	First line at standard dose, second line consider dose increase up to fourfold	Antagonism or inverse agnosim of H1 receptor, preventing histamine effects
First-generation H1 antihistamines (eg, hydroxyzine)	Third line	Antagonism or inverse agnosim of H1 receptor, preventing histamine effects
H2 antihistamines (eg, cimetidine)	Third line	Unclear in urticaria, may have small additive effect with H1 antihistamines
Acetylcholine antagonists (eg, scopolamine)	Adjuvant with H1 antihistamines	May prevent histamine release
Phototherapy (eg, psoralen plus UVA, UVB)	Adjuvant with oral therapy or second-line alone	Reduction of mast cell activity, reactive thickening of the epidermis
Topical barrier creams (eg, petrolatum)	First line or adjuvant	Hydrophobic effect prevents water penetration into skin
Anabolic androgenic steroid (eg, stanozolol)	Case-specific, used in HIV patient with AU	Increases C1 esterase inhibitor synthesis
Selective serotonin reuptake inhibitors (eg, fluoxetine)	Case-specific, used in patient with extracutaneous symptom of AU	Unknown

Note: Adapted from McGee JS, Kirkorian AY, Pappert AS, Milgraum SS. An adolescent boy with urticaria to water: Review of current treatments for aquagenic urticaria. Pediatr Dermatol. 2014;31(1):116–117. Copyright 2011 Wiley Periodicals, Inc.²²

Abbreviations: AU, aquagenic urticaria; HIV, human immunodeficiency virus, UV, ultraviolet.

KomarowHDArceoSYoungMNelsonCMetcalfeDDDissociation between history and challenge in patients with physical urticariaJ Allergy Clin Immunol Pract20142678679025439372

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McGeeJSKirkorianAYPappertASMilgraumSSAn adolescent boy with urticaria to water: review of current treatments for aquagenic urticariaPediatr Dermatol201431111611722994854

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