Alitretinoin abrogates innate inflammation in palmoplantar pustular psoriasis

Background Palmoplantar pustular psoriasis is often recalcitrant to therapy. Here we evaluated the therapeutic effect of alitretinoin in patients with recalcitrant palmoplantar pustular psoriasis and investigated subsequent immunopathological alterations. Methods Seven patients with palmoplantar pustular psoriasis were treated with oral alitretinoin 30 mg once daily for 12 weeks. Efficacy was assessed by palmoplantar pustular psoriasis area and severity index (PPPASI), visual analogue scales (VAS) on intensity of pain and pruritus and an overall patient assessment. Immunohistochemical staining for neutrophil elastase, CD3, CD4, CD8, CD1a CD11c, CD303,CD68, CD69, CD208 and HLA‐DR was on lesional skin biopsies obtained before and after 12 weeks of treatment. Results PPPASI and VAS for pruritus and pain decreased significantly after 12 weeks of treatment with alitretinoin. The overall patient assessment ranged from 60% to 90% clinical improvement. In correlation with clinical improvement a significant reduction, particularly of neutrophils, macrophages and dendritic cells, was also observed in the skin sections. Alitretinoin was well tolerated except for headache during the first month of treatment in two patients. Limitations of the study are a missing control group and the concomitant usage of topical therapy. Discussion Our findings suggest that alitretinoin may represent a new and promising therapy for recalcitrant palmo‐plantar psoriasis and warrants further controlled studies to confirm efficacy and safety of alitretinoin in this disease.