This study is evaluating the efficacy of methotrexate injections for treatment of nail psoriasis.

Participants in this study will receive three injections into three different nails: one nail will receive methotrexate, one nail will receive triamcinolone acetonide, and one nail will receive a placebo (no medication) injection.

Triamcinolone acetate and methotrexate are both approved by the U.S. Food and Drug Administration, however, nail injections for nail psoriasis are not an approved use of methotrexate by the FDA.

On the first study visit, three nails affected by psoriasis will be randomly selected. The selected three nails will be randomly assigned to one of the two medications (methotrexate, triamcinolone acetonide) or a placebo (no medication). If a participant has more than three nails affected by psoriasis, normal standard of care will be offered for the nails not enrolled in the study. Patients will also need a nail clipping, Xray, and pregnancy test (if applicable) at their screening visit. 

Over the study, the three nails will receive the assigned injection into the same nail every 6 weeks for 3 sessions total. Each nail injection session will take approximately 2 minutes and fingernails will be photographed at every visit. At each visit, blood will be taken to monitor liver and blood. 

The trial will consist of 6 appointments: a screening visit, 3 study intervention visits (once every 6 weeks +/- 1 week), and 2 follow up visits (one 1-month after last nail injection and once 6-months after last nail injection). This is the same number of appointments as standard nail psoriasis treatment.