Contact allergy in psoriasis

Introduction: The opinions about the occurrence of the contact allergy and psoriasis differ.

Aims: To assess the frequency of contact allergy among patients with psoriasis.

Material and methods: Meta-analysis of clinical-epidemiological publications concerning the frequency of contact allergy among psoriasis patients. Pooled frequencies with confidence intervals (95%CI) were presented in comparison to estimates of frequencies of contact allergy in the general population (Schäfer et al. 2001).

Results: The pooled frequency of contact allergy among patients with psoriasis in all analyzed publications was 21.6% (95%CI 18.8-24.5%). Most patients were allergic to nickel (8.8%; 95%CI 6.6-10.8%; frequency in the general population according to Schafer: 9.9%). Other haptens that commonly sensitized psoriasis patients were: diaminodiphenylmethane (3.3%; 95%CI 1.3-5.3%; estimates for general population not available), fragrance mix (3.3%; 95%CI 1.5-3.9%; Schäfer: 11.4%), thiomersal (2.6%; 95%CI 1.0-4.0%; 3.2%), neomycin (2.4%; 95%CI 1.2-3.7%; 1.3%), paraphenylenediamine (2.5%; 95%CI 1.1-3.4%; 3.2%), chromium (2.6%; 95%CI 0.9-3.2%; 0.8%). Among patients with psoriasis, contact allergy to topical drugs used for treating this disease also occurs quite often: 4.7% of all patients with psoriasis were allergic to dithranol, 5.2% to coal tar and 11.8 to wood tar mix.

Conclusions: The frequency of contact allergy among psoriasis patients is similar to that in the general population. Rare allergy to fragrance mix among psoriasis patients is an exception, which could result from a more cautious use of perfumes in this group. The relatively high frequency of contact allergy to antipsoriatic drugs is of particular relevance taking into consideration the long-lasting topical treatment.

Related articles:

1. Spiewak R. Köbnerizing occupational contact allergy to thiuram in a farmer with psoriasis . Contact Dermatitis 2004, 51 (4): 214-215.
2. Spiewak R. Patch testing for contact allergy and allergic contact dermatitis. Open Allergy J 2008, 1: 42-51.

Links:

Institute of Dermatology, Krakow, Poland

International Photopatch Test Course, Krakow 2009

English-speaking dermatologist in Krakow (Cracow), Poland

Deutschsprechender Hautarzt in Krakow (Krakau), Polen

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