Guidelines for the treatment of nail lichen planus (NLP) in the context of the coronavirus disease 2019 (COVID-19) pandemic were provided in a letter to the editor published in Dermatologic Therapy. Authors described NLP as a “true nail emergency,” sometimes resulting in permanent nail loss or scarring. Immunosuppressants are a key element in NLP treatment, but may increase risk for COVID-19-related mortality. In their article, investigators weighed the efficacy of NLP therapies against the risk for increased susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Triamcinolone acetonide (TAC) is typically considered first-line therapy for NLP. Often, TAC is injected directly into the lesion. Side effects are mild, and risk for systemic toxicity is low. However, TAC administration necessitates an office visit. To comply with social distancing recommendations, investigators wrote, dermatologists should avoid performing TAC injections. In the case of severe, progressive NLP which does not respond to other therapies, exceptions may be necessary. Generally, however, in-person visits should be minimized.
Retinoids are considered second-line treatment for NLP and can be prescribed without an in-person office visit. Retinoids are known to cause immune suppression, although not to the same extent as systemic corticosteroids. No retinoid-related NLP infections have been reported in the literature. In addition, retinoids have been observed to inhibit the replication of certain viruses, including human herpesviruses, human immunodeficiency virus, hepatitis B virus, and hepatitis C virus. However, the effectof retinoids on SARS-CoV-2 remains unknown, the authors wrote. Even so, investigators emphasized retinoids as a therapeutic alternative to TAC injections.
Third-line treatments for NLP include immunosuppressant medications azathioprine, cyclosporine, and mycophenolate mofetil. Although in vitro studies have identified anti-coronavirus activity in cyclosporine, the overall effect of these treatments on SARS-CoV-2 susceptibility remains unclear. Generally, immunosuppressant drugs should be avoided during the pandemic, particularly in patients who exhibit symptoms for COVID-19. One case study supported the efficacy of chloroquine with hydroxychloroquine for NLP treatment. In vitro studies suggest these drugs may inhibit SARS-CoV-2, although the extent of this inhibition remains unclear. As such, treatment with chloroquine and hydroxychloroquine for NLP is not recommended.
The COVID-19 pandemic requires cautious selection of pharmacologic treatment for NLP, the authors noted. Retinoids may be the safest option for patients, although treatment plans should be developed on a case-by-case basis. In-person office visits and systemic immunosuppressants should be avoided. Further study is needed to assess the direct impact of these drugs on SARS-CoV-2 susceptibility.
Ricardo JW, Lipner SR. Recommendations for treatment of nail lichen planus during the COVID-19 pandemic [published online May 10, 2020]. Dermatol Ther. doi: 10.1111/dth.13551