Physical urticarias, aquagenic pruritus, and cholinergic pruritus



Physical urticarias, aquagenic pruritus, and cholinergic pruritus


Clive E.H. Grattan and Frances Lawlor


Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports


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Physical urticarias


About 25% of patients with chronic urticaria have a definable and reproducible physical trigger that distinguishes them from those with spontaneous urticaria and urticarial vasculitis. Physical urticarias are defined by the predominant stimulus that induces them (Table 181.1). More than one physical stimulus elicits urticaria in some patients, and physical urticarias can overlap with spontaneous urticaria. Physical urticarias are included under the term ‘inducible urticarias’ in the latest European classification.




Management strategy


Pharmacologic


The clinical presentation of the physical urticarias may vary considerably in severity. Drug management should be guided by the degree of disability and impairment in quality of life. The milder forms may require little more than explanation, avoidance of situations likely to trigger an attack, and an occasional dose of antihistamine, whereas a very severe attack involving anaphylaxis would require emergency treatment with intramuscular epinephrine (adrenaline). Acute presentations of severe physical urticaria may require short courses of oral corticosteroids (e.g., prednisolone 30–40 mg daily for 5 days) in addition to regular treatment with non-sedating H1 antihistamines.




Specific investigations






With the exceptions of testing for cryoglobulins, in secondary cold urticaria and specific IgE in food- and exercise-induced anaphylaxis, routine laboratory investigations are unnecessary and should not be undertaken except to monitor treatment or screen for eligibility (e.g., glucose-6-phosphatase dehydrogenase in patients being considered for dapsone or sulfasalazine).










First-line therapies









imageNon-sedating (‘second generation’) antihistamines A


Non-sedating antihistamines (Table 181.2) should be prescribed in preference to classical antihistamines, which are often sedating and can impair psychomotor performance. Up-dosing of second generation H1 antihistamines is often practiced.










Second-line therapies


Symptomatic dermographism


















imageH2 receptor antagonists A
imageNarrowband UVB phototherapy C
imagePhotochemotherapy (PUVA) C
imageOmalizumab E









Cholinergic urticaria


















imageDanazol A
imageAnticholinergics E
imageAutologous sweat injection D
imageOmalizumab E







Rapid desensitization with autologous sweat in cholinergic urticaria.


Kozaru T, Fukunaga A, Taguchi K, Ogura K, Nagano T, Oka M, et al. Allergol Int 2011; 60: 277–81.


Six patients with H1 antihistamine-unresponsive cholinergic urticaria were injected intradermally with 1/1000 then 1/100 dilutions of autologous sweat at increasing volume (0.02–0.2 mL) hourly followed by a weekly maintenance injections of 0.1 mL of 1/100 diluted sweat for several months. All patients showed a reduced skin test reaction to sweat after the initial rapid desensitization and five had an improvement in their cholinergic urticaria symptoms during the maintenance period.


The study was conducted in one center and was uncontrolled so it is unclear how much of the subjective clinical improvement was due to the treatment.




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Aug 7, 2016 | Posted by in Dermatology | Comments Off on Physical urticarias, aquagenic pruritus, and cholinergic pruritus

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