Case Report: Psoriasiform acral dermatitis successfully treated with upadacitinib: clinical evidence of JAK1-targeted therapy

Psoriasiform acral dermatitis (PAD) is an uncommon and likely underrecognized inflammatory dermatosis characterized by a psoriasiform–spongiotic phenotype with preferential involvement of distal digits and/or acral surfaces. Its nosologic status remains debated, and therapeutic responses to conventional topical measures, keratolytics, vitamin D analogues, retinoids, and immunomodulators are often limited or transient. We report two PAD cases successfully treated with the JAK1-selective inhibitor upadacitinib. The first case involved a 35-year-old man with chronic, progressively symptomatic hyperkeratotic, thickly scaling plaques affecting distal phalanges and palms, associated with marked xerosis and painful fissuring, as well as concomitant eczematous cheilitis. Baseline hematochemical tests were normal, and abdominal ultrasound plus chest x-ray were unremarkable, with no findings suggestive of occult malignancy in the differential (including Bazex syndrome). Upadacitinib 15 mg once daily led to complete clearance within two months, excellent tolerability, and no relapse after 10 months of follow-up under maintenance therapy. The second case was a 14-year-old boy with long-standing, treatment-refractory palmoplantar acral disease causing functional impairment after multiple systemic and biologic therapies; upadacitinib 15 mg once daily induced near-complete improvement within two weeks. These observations provide initial clinical evidence supporting JAK1 inhibition as a targeted option for severe, refractory PAD.