Contact sensitivity in patients with psoriasis in Vojvodina

Immunologic studies indicate that psoriasis may represent an organ-integrated response.

We assessed contact hypersensitivity in plaque-type psoriasis, its frequency, etiology and association with severity of psoriasis.

Contact hypersensitivity was defined as a positive patch test (PT) to at least one of 44 ubiquitous contact allergens. Patients with exclusively plaque psoriasis and control groups (patients with allergic contact or extrinsic atopic dermatitis and healthy persons) were tested with the European standard series; plant-related standard allergens; Compositae allergens, and our own extracts from Compositae plants ubiquitous in Vojvodina. Sensitization rates to allergens were standardized for age and sex, and rates in women and in men were both standardized for age. Disease severity was evaluated using the Psoriasis Area Severity Index score.

15,123 PTs were performed. Among psoriatic patients in Vojvodina, the overall rate of sensitivity, standardized for age and sex, was 18.9%. Rates in women (27.7%) and men (5.8%), both standardized for age, were significantly different. Male psoriatic patients reacted less than healthy males, the difference being on the margin of significance. There was no relationship between severity of disease and PT reactivity. Yarrow extract, nickel and a Compositae mix were the most common allergens that produced positive reactions.

Although patch testing in psoriatic patients can be quite challenging, time-consuming and difficult, it will provide further insight into the pathophysiology of psoriasis. Factors other than different exposure to allergens may also be responsible for a sex-related difference in contact sensitivity. Future studies should focus on this field.