Background: Phosphodiesterase inhibitors are commonly used drugs.  Specific phosphodiesterase inhibitors with anti-inflammatory properties are being assessed as dermatological treatments.

Purpose:  To describe important aspects of phosphodiesterase inhibition and the safety and efficacy of 2 phosphodiesterase- 4 inhibitors being studied for the treatment of dermatologic diseases

Methods: We did a non-systematic analysis of literature on phosphodiesterase inhibition followed by a review of published information on apremilast and topical AN2728 and their use for psoriasis and atopic dermatitis.

Findings: Apremilast and topical AN2728 have modest efficacy in treatment of psoriasis. Apremilast achieved PASI-75 scores ranging from 24-33%. In phase 2 studies, AN2728 had modest efficacy for psoriasis (40% of patients achieved a ≥ 2 grade improvement as assessed by the Overall target Plaque Severity Score).   In phase 2 studies of AN2728 use in atopic dermatitis, subjects achieved a 71% improvement from baseline Atopic Dermatitis Severity Index. In all studies, most adverse effects were minimal. The limitations of this paper are the limited number of published studies, the lack of long-term data, and the lack of head -to - head trials directly comparing phosphodiesterase inhibitors with other treatments.

Conclusion: Phosphodiesterase inhibitors constitute a widely used class of drugs that may see growing use for inflammatory dermatologic diseases.