Single-group, randomized, single-blind, intra-patient controlled study arm. Participants are assigned to treatment according to diagnosis: participants with non-palmoplantar plaque psoriasis receive PROXERA PSOMED 20 once daily for 4 weeks on one target plaque, while participants with non-pustular palmoplantar psoriasis receive PROXERA PSOMED 40 once daily for 8 weeks on one target palm or sole area. In both cohorts, a comparable contralateral target area remains untreated as control. For PROXERA PSOMED 40, treatment is interrupted for 3 days every 14 days.

Participants with non-pustular palmoplantar psoriasis self-apply PROXERA PSOMED 40 once daily at the same time of day to one target palm or sole area for 8 weeks. The dose is applied according to the fingertip unit rule. A comparable contralateral target area remains untreated as control. Treatment is interrupted for 3 days every 14 days.

Proxera Psomed 20: Topical medical device in cream formulation containing 20% urea, supplied in a 200 mL tube. It is self-applied by the participant once daily at the same time of day to the selected target plaque for 4 weeks, according to the fingertip unit rule. The contralateral comparable target area remains untreated as control.

Proxera Psomed 40: Topical medical device in gel formulation containing 40% urea, supplied in a 100 mL tube. It is self-applied by the participant once daily at the same time of day to the selected target palm or sole area for 8 weeks, according to the fingertip unit rule. Treatment is interrupted for 3 days every 14 days. The contralateral comparable target area remains untreated as control.

Proxera Psomed 20: Target Lesion Score (TLS) is a semi-quantitative clinical score used to assess the severity of a representative psoriatic plaque. Three plaque characteristics are evaluated separately: erythema, induration (thickness), and scaling. Each item is scored from 0 to 4, and the total TLS ranges from 0 to 12, with higher scores indicating more severe disease. The primary analysis compares the change from baseline to Week 4 in the treated target plaque versus the untreated contralateral control area.

Proxera Psomed 40: Modified Palmoplantar Psoriasis Area and Severity Index (mPPPASI) is a clinical score used to assess the severity of non-pustular palmoplantar psoriasis. The score evaluates erythema, induration, scaling, and extent of involvement in the palmoplantar target area. Higher scores indicate more severe disease. The primary analysis compares the change from baseline to Week 8 in the treated target palm or sole area versus the untreated contralateral control area.