Palmoplantar hyperkeratotic psoriasis with a combination of adalimumab and alitretinoin: Clinical and histologic finding

Background: Palm and sole psoriasis occours approximately in 15% of patients. Occupational manual workers are especially at risk and the isomorphic Koebner reaction may actually contribute to significant palmar hyperkeratosis even refractory to biologics. Oral alitretinoin (9-cis retinoic acid), which has been emerging as novel treatment for recalcitrant chronic hand eczema, is a vitamin A derivative with immunomodulatory and antiinflammatory activities. The specific alitretinoin mechanism of action which finally leads to skin inflammatory changes improvement is still far from being understood. We evaluated the therapeutic effect of alitretinoin plus adalimumab in patients with recalcitrant palmoplantar psoriasis thus investigating subsequent immunopathological alterations. Methods: Fifteen patients with palmoplantar psoriasis were treated with oral alitretinoin 30 mg once daily for 12 weeks plus adalimumab 40 mg once every 2 weeks. Efficacy was assessed by PASI, Palmoplantar Pustular Psoriasis Area and Severity Index (PPPASI), visual analogue scales (VAS) on intensity of pain and pruritus along with an overall patient assessment. Immunostaining for TNFα, p40 IL12-23, RAR, and RXR was performed from skin lesions biopsied before and after 12 weeks of treatment. Results: PASI, PPPASI and VAS for pruritus and pain decreased significantly after 12 weeks of treatment with adalimumab plus alitretinoin. The overall patient assessment ranged from 60 to 90% clinical improvement. A significant reduction of TNFα, p40 IL12-23, RAR and RXR at immunohistochemistry was also observed reflecting clinical improvement. Discussion: Our findings suggest how alitretinoin may be used effectively in combination with adalimumab in patients with refractory palmoplantar hyperkeratotic psoriasis. Future randomized trials are required to confirm the safety and efficacy of such therapeutic option.