Linear chronic discoid lupus erythematosus following the lines of Blaschko.

Linear chronic discoid lupus erythematosus is a rare manifestation of cutaneous lupus in which erythematous, atrophic, dyschromic lesions are located along the lines of Blaschko. This report describes the case of a 15-year old boy with a 2-year history of discoid, erythematous, hyper and hypopigmented lesions with central atrophy, situated along the lines of Blaschko on his right arm. Histopathology showed epidermal atrophy, hyperkeratosis, follicular plugging, thickening of the basement membrane zone, and superficial and deep chronic perivascular and periadnexal inflammatory infiltrate, with dermal mucin deposit, thus confirming diagnosis. A total of 14 cases have been described of this variant, the onset of which is often in childhood. There is no difference in incidence between genders. Lesions most commonly develop on the face. There have been no reports of any association with systemic disease.