Cutaneous hypersensitivity to Malassezia sympodialis and dust mite in adult atopic dermatitis with a textile pattern

Atopic dermatitis (AD) patients with predominantly head and neck involvement react to patch tests of the yeast Malassezia sympodialis (Ms). Protein patch testing methods and interpretation are controversial, but subgroups of AD patients may have unique triggers for disease activity. The aim of the study was to identify clinical characteristics of patients who are patch test-positive to Dermatophagoides farinae/pteronyssinus (Df) and Ms and characterize cutaneous cytokine profiles of the atopy patch tests (APTs). 25 AD patients and 27 control dermatitis patients were patch tested with Ms and Df. Qualitative analysis of Th-1 and Th-2 cytokines by RT-PCR mRNA was obtained from positive APTs. Atopic dermatitis patients with a textile pattern or head and neck involvement demonstrated more positive APTs to Ms than control patients. Early positive APTs (< 6 hr) did not exhibit a Th-1 type cytokine profile. The subgroup of adult AD patients with head, neck and upper torso pattern of dermatitis seems most likely to react to Ms (and Df). The immune mechanism of protein patch tests includes a Th-1 cell-mediated component after 6 hr or more.