Unilateral unique Lupus tumidus: pathogenetic mystery and diagnostic problem

Lupus tumidus is a rare immunological disorder whose pathogenesis is not fully understood. Although on the one hand there are some differences in (1) the clinical morphology of lesions, (2) the histopathology picture, as well as in (3) serological profile of lupus tumidus patients at the current moment, the disease is regarded as a subform of chronic cutaneous lupus erythematosus. Differential diagnosis requires the exclusion of many diseases such as Jessner Kanoff lymphocytic infiltration, polymorphous light eruption, and reticular erythematous mucinosis. Differentiation between them is not always easy. The standard treatment regimen of patients with lupus tumidus is based on local and systemic application of corticosteroids, azathioprin, dapsone, mepacrine, chloroquine, and hydroxychloroquine. Modern treatment options include the use of pulsed dye laser, tacrolimus 0.1 % ointment and photophoresis. We present a 42-year-old patient with unilateral atypical form of lupus tumidus who was successfully treated with systematically administration of hydroxychloroquine in combination with sunscreen SPF 50. After a 2-month course of treatment with hydroxychloroquine dosage of 200 mg per day and a break of 3 months between courses, we observed a complete remission.