Sweat gland abnormalities in lichenoid dermatosis

Lichenoid dermatosis is a pattern description of a variety of cutaneous lesions which primarily affect the dermoepidermal junction. Involvement of skin appendages has been restricted to hair follicles in lichen planopilaris and discoid lupus erythematosus. Sweat gland involvement has not been described in the four common members of this group, namely, lichen planus, discoid lupus erythematosus, fixed drug eruptions and erythema multiforme, although structural abnormalities have been reported in graft-versus-host disease. In a detailed morphological study of 59 cases, including lichen planus (12), discoid lupus erythematosus (18), fixed drug eruption (14) and erythema multiforme (15), 78% (47/59) showed sweat, gland abnormalities. The abnormalities included vacuolation of cell cytoplasm, with and without lymphocytic infiltration, apoptosis of basal cells and basal cell hyperplasia of the excretory ducts which predominantly affected the portion of the duct adjoining the acrosyringium. The portion of the duct close to the secretory gland was only involved in continuity and the secretory glands were unaffected. These abnormalities of the sweat gland mostly constitute primary involvement by the disease process in contrast to structural abnormalities secondary to fibrosis.