Linear Cutaneous Lupus Erythematosus Following Blaschko's Lines on the Scalp: Additional Cases and Review of the Literature

Description Alopecia of the scalp has various causes and presentations. However, linear alopecia is unusual and lupus erythematosus presenting as linear alopecia is exceedingly rare. To date, there have been 16 documented cases of linear alopecia diagnosed as chronic cutaneous lupus erythematosus occurring in a linear configuration following Blaschko's lines. We report 2 additional cases and review the clinical and histologic features along with treatment. This Blaschkoid linear variant of cutaneous lupus erythematosus has distinct clinical and histologic characteristics that set it apart from other causes of alopecia and from classic forms of cutaneous lupus. These distinct features include a linear configuration, a younger age of presentation, a disproportionate number of Asians affected, and a paucity of cases with systemic involvement. Histologically, the lesions are characterized by prominent mucin in the dermis and subcutaneous tissues. Blaschkoid linear lupus of the scalp is sufficiently distinctive to suggest the diagnosis on histology alone, in the appropriate clinical context. The most common and successful treatments included systemic and/or combination treatment with oral hydroxychloroquine, oral steroids, and/or intralesional steroids.