Cholinergic urticaria

In some individuals, urticarial weals are provoked by physical stimuli, e.g. friction (dermographism), heat or cold. Exercise may induce weals, particularly on the upper trunk (cholinergic urticaria). Physical urticarias may require combined Hj- and receptor receptor antagonists fully to block the vascular effects of histamine, which causes flushing and hypotension. Cyproheptadine is usually the preferred choice of Hj-antihistamine but causes drowsiness. 

Physical urticaria is classified according to the nature of the eliciting stimulus, i.e., mechanical, thermal or electromagnetic (Table i). Rarely, urticaria has also been reported in association with decompression and with X-ray and argon laser treatment (reviewed in Henz et al. 1997). Cholinergic urticaria is often classified as physical urticaria since an increase in body heat is involved. Aquagenic urticaria is elicited by a chemical rather than a physical stimulus to the skin surface, with the water dissolving a water-soluble... 

Physical exercise, stress Cholinergic urticaria 2-20 min 0.5-1 Exercise until sweating... 

Fig. 2. Typical appearance of cholinergic urticaria, with tiny, itching wheals on the upper arm, 5 min after physical exercise (picture from Henz et al. (1997))...

Cholinergic urticaria has a prevalence of 11.2% among young adults (16-35 years old), with a maximum of 20% in subjects aged 26-28 years (Table 2), although clinical manifestations are rarely severe and bothersome in daily life (11%) (Zuberbier et al. 1994). 

The disease must be differentiated from solar urticaria and cholinergic urticaria (heat reflex urticaria) by appropriate testing (see above). 

Czarnetzki BM, Galinski C, Meister R (1984a) Cutaneous and pulmonary reactivity in cholinergic urticaria. Br J Dermatol... 

Zuberbier T, Althaus C, Chantraine-Hess, Czarnetzki BM (1994) Prevalence of cholinergic urticaria in young adults. J Am Acad Dermatol 31 978-981... 

Zuberbier T, Aberer W, Burtin B, Rihoux J-P, Czarnetzki BM (1995) Efficacy of cetirizine in cholinergic urticaria. Acta Derm Venereol Suppl (Stockh) 75 147-149... 

Cholinergic urticaria (°) Bathing or swimming in warm water... 

Kaplan, A. P., Gray, L., Shaff, R. E., Horakova, Z., and Beaven, M. A., 1975, In vivo studies of mediator release in cold urticaria and cholinergic urticaria, J. Allergy Clin. Immunol. 55 394-402. 

Although the pathogenesis of exercise-induced allergy (EIA) is poorly understood, biopsy studies have demonstrated mast cell degranulation after exercise. Patient s with EIA who have specific foods as coprecipitating factors invariably have positive skin test reactions to these foods, thus specific IgE mast cell sensitization is indicated. A potential dysfunction in the autonomic nervous system has also been hypothesized. Differential diagnosis includes cholinergic urticaria. 

---