Contact hypersensitivity in patients with primary cutaneous lymphoproliferative disorders

Background  One of the suggested causes of primary cutaneous lymphoproliferative disorders is persistent antigenic stimulation. Objective  To study the prevalence of contact hypersensitivity in patients with primary cutaneous lymphoproliferative disorders other than mycosis fungoides (MF). Materials and methods  Thirty consecutive patients with primary cutaneous lymphoproliferative disorders other than MF were patch tested to a European Standard & partial metal series. The results were compared with those of 792 consecutive patients with other skin diseases referred to our clinic and a large published series of 9760 healthy individuals from North America. Results  Twenty-two patients with primary cutaneous lymphoma other than MF and eight patients with pseudolymphomas were included in the study. Altogether there were 23 positive patch tests in 13 patients. Only the prevalence of positive patch tests to cobalt (5/30 patients = 17%) was found to be significantly higher in the studied group than in the two control groups (P < 0.01 and P = 0.05, respectively). The contact hypersensitivity to cobalt and the other allergens, however, could not be related causally to the pathogenesis of the lesions. Conclusions  The relative prevalence of contact hypersensitivity to cobalt only was found to be increased in a group of primary cutaneous lymphoproliferative disorders, but a causal relationship to the lymphoproliferative disorders could not be established.