Phenytoin inhibits inflammation in the skin

In dermatological conditions, topical phenytoin has been evaluated in the treatment of ulcers, epidermolysis bullosa, and in other inflammatory conditions of the skin. Topical phenytoin (2% to 5% in cream) was effective in treating the ulcers of epidermolysis bullosa simplex, and has also been used in treating discoid lupus erythematosus.

In a recent study in 28 patients from Dermatology Outpatient Clinic, Faculty of Medicine, Menoufia University, USA phenytoin was tested in vitiligo. After treatment punch biopsies were taken from patients under local anesthesia from the lesional skin. Patients were treated with a topical phenytoin 2% gel twice daily for 3 months duration. The ratio for the concentration of 2% was not given.

Sixteen out of 28 investigated patients were evaluated by a post phenytoin therapy biopsy after 3 months duration from starting therapy. The results showed that the presence of dermal inflammatory cells have been decreased. Moderate density of inflammation was identified in 4 patients before therapy (4/16, 25%) compared to 2 patients after receiving phenytoin (2/16, 12.5%). Inflammation density was higher in responders compared to non-responders, and nearly reached statistical significance. The study however tested phenytoin only as 2% concentrated gel and only for 3 months, which is a relatively short duration for the indication; there were no side effects reported. The conclusion was: “These results indicate that topical phenytoin of low concentrations may have beneficial effects through immunomodulatory activity by affecting CD4 and CD8 counts and subsequently the ratio between them.”

Source: Abdou AG, Abdelwahed Gaber M, Elnaidany NF, Elnagar A. Evaluation of the effect and mechanism of action of local phenytoin in treatment of vitiligo. J Immunoassay Immunochem. 2017;38(5):523-537. doi: 10.1080/15321819.2017.1344129.