La risposta cutanea dermografica nei pazienti con orticaria o psoriasi

Background: physical urticarias (Us) represent about 20% of all cases of acute or chronic Us. Among these patients, the most common are those affected by immediate dermographism. In patients affected with U and in those with psoriasis different mechanical injuries can induce cutaneous lesions represented, respectively, by wheals and psoriatic lesions. Objective: our purpose was to evaluate the skin response to mechanical stimulation obtained by a dermographometer in patients with different forms of U or psoriasis. Material and methods: 65 subjects affected with U, 40 with psoriasis, 48 control subjects and 42 patients with different cutaneous disorders, where any fundamental role could be attributed to mast cells, were evaluated. Results: on testing with a dermographometer, in all patients with dermographic U a linear wheal appeared in a few minutes. A similar positive response was obtained in 3 of 6 patients with pressure U, 1 of 3 with cold U, and 2 of 5 with cholinergic U. 9 of 29 subjects with idiopathic U reacted in the same way, too. In patients with psoriasis 10 of 40 positive responses with the instrument were obtained. Nevertheless, only one third of them reacted to pressures below normal limits (≤9 arbitrary units). Therefore, in this study psoriatic patients' response did not differ from that of control subjects. No abnormal response was also observed in the group of patients with other cutaneous disorders (allergic contact dermatitis, irritant contact dermatitis, vitiligo, icthyosis).