This Month in Archives of Dermatology

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate and homocysteine metabolism. Genetic polymorphisms are associated with thrombophilia and vasculopathy, which result in cutaneous ulceration. In this case series, New et al describe 2 patients who were found to have MTHFR polymorphisms during hypercoagulable evaluation for cutaneous ulceration on the lower extremities. Both patients showed rapid improvement following oral B-vitamin supplementation and local wound care. MTHFR polymorphisms should be part of a comprehensive laboratory evaluation when performing a hypercoagulable workup.

Lichen planus is a common inflammatory autoimmune condition that commonly affects the skin and mucous membranes. Ocular involvement is rare, but isolated conjunctival lichen planus is a rare cause of cicatricial conjunctivitis. In this case report, Muñoz et al describe a 79-year-old man with chronic refractory keratoconjunctivitis in the absence of any other skin or mucosal lesions. Biopsy specimens analyzed under direct immunofluorescence revealed changes suggestive of lichen planus. The patient's clinical findings improved following treatment with oral corticosteroids and azathioprine, demonstrating how early anti-inflammatory treatment can avoid irreversible visual loss.

Xanthoma disseminatum (XD) is a rare, benign condition in which lipid deposition occurs secondary to histiocyte proliferation resulting in cutaneous xanthomatous lesions in the flexural areas along with ocular, oral, pharyngeal, visceral, skeletal, and central nervous system involvement. No known trigger has been identified, and response to therapy is usually unsatisfactory. In this case series, Khezri et al report 8 cases of XD, 5 of which showed substantial improvement after administration of the purine nucleoside analogue 2-chlorodeoxyadenosine (2-CdA), which was previously reported to be useful in treating Langerhans cell histiocytosis. No serious toxic effects were noted, suggesting that 2-CdA may represent one of the first useful therapeutic options reported for XD.

Moderate to severe chronic plaque psoriasis of the hands and feet occurs infrequently. Despite the relatively small body surface area involvement, this psoriasis subset has a disproportionately negative impact on quality of life. Treatment is often unsatisfactory. Topical therapies and phototherapy are sometimes ineffective, and systemic therapies may be limited by adverse effects. In this randomized, double-blind, placebo-controlled study, Leonardi et al demonstrate that adalimumab is efficacious in treating adults with moderate to severe chronic plaque psoriasis on the hands or feet. Lesions on the palms responded better than those on the soles, and nail involvement was noted to improve as well. Adalimumab was well tolerated and posed a low risk of serious adverse events.

Polymyositis (PM) and dermatomyositis (DM) represent a group of chronic inflammatory disorders characterized by myogenic changes and/or skin eruptions. A variety of diagnostic autoantibodies (Abs) are associated with clinically distinct subsets of PM and DM. Identification of these Abs is useful in defining clinically homogeneous patient subsets and predicting prognosis. In this retrospective study, Hamaguchi et al evaluate all currently available myositis Abs for patients with DM, focusing on 3 highly DM-specific Abs: anti–Mi-2 and the more recently described anti–155/140 and anti–CADM-140. These DM-specific Abs were mutually exclusive, and each defined a clinically distinct phenotype. Classifying patients with DM according to these Abs may guide the physician to focus on particular manifestations at higher risk.