“Are we, as dermatologists, testing or treating for onychomycosis?” asked Shari Lipner, MD, PhD, in her session on diagnostic, therapeutic, and surgical nail pearls at the 2019 American Academy of Dermatology (AAD) Summer Meeting.1
The answer? Research indicates that most dermatologists test and treat for this condition, but some are still not testing, and this kind of testing is even less common among podiatrists, internists, and family medicine physicians, she said.
“There are many reasons to test before treatment, including avoidance of missed diagnoses, treatment failures, and avoiding adverse effects,” said Dr Lipner, who is an assistant professor of dermatology and assistant attending physician at New York-Presbyterian Hospital and Weill Cornell Medical Center.
As part of the Choosing Wisely campaign, the AAD has stated that antifungal therapy should not be prescribed without performing confirmatory testing for fungal infections like onychomycosis,2especially when it comes to ruling out differential diagnoses like nail psoriasis and squamous cell carcinoma (SCC) of the nail. In patients whose diagnosis turns out to be SCC, prescribing an antifungal drug like terbinafine would lead to “disastrous” adverse effects, Dr Lipner emphasized.
She described traditional methods of diagnosis, including KOH with microscopy, fungal culture, a clipping with histopathology, and molecular biology. Each of these options has advantages and disadvantages depending on the speed of obtaining results, varying levels of sensitivity and specificity, and ability to pinpoint the identity and viability of organisms in a culture, among others.
Next, Dr Lipner delved into therapeutic pearls for nail diagnoses, especially those related to nail psoriasis. She noted that 90% of patients with psoriasis will develop psoriasis of the nail in their lifetime, and that 80% of patients with psoriatic arthritis will have it as well.
Diagnoses can vary based on part of the nail affected and the number of nails involved. ‘Few nail’ disease occurs when 3 or fewer nails are affected, and ‘many nail’ disease occurs when more than 3 nails are impacted and is often accompanied by joint involvement and quality of life issues.
Although evidence is somewhat limited for the treatment of nail psoriasis, patients with ‘many nail’ diseases are typically treated with topicals in combination with either systemics or biologics, Dr Lipner said. For ‘few nail’ disease affecting only the nail bed, the nail is typically clipped and then treated with a strong topical steroid with or without vitamin D analogues, she explained. Intralesional injections with Kenalog (triamcinolone acetonide) into the nail matrix are the treatment of choice for nail matrix psoriasis, she added.
Finally, Dr Lipner touched on surgical nail pearls, stating that nail biopsies are needed to confirm diagnoses, but that nail surgery hemostasis is often challenging because the nail unit is vascular and bleeding can be profuse during surgical interventions. Current methods to achieve nail surgery hemostasis include direct pressure, aluminum chloride, and gelatin, among others, but there is a need for more effective strategies here, Dr Lipner said.
She also overviewed the use of gel and topical treatments for nail surgery, noting that with certain precautions, brimonidine gel can safely be used for hemostasis following nail surgery.
Dr Lipner concluded her session by reiterating 3 key clinical takeaways:
- Always perform confirmatory testing prior to therapy initiation for onychomycosis.
- Perform intralesional nail matrix injections with Kenalog (triamcinolone acetonide) as first-line treatment for nail matrix psoriasis. This can be used alone for cases of limited nail disease and as an adjunct therapy for more extensive cases of nail disease.
- Brimonidine gel may be safely used for hemostasis after nail surgery, but certain precautions should be taken.
1. Lipner S. Pearls from members: nails pearls. Presented at: 2019 American Academy of Dermatology Summer Meeting; July 25, 2019; New York, NY. https://www.aad.org/scientificsessions/sam2019/SessionDetails.aspx?id=12730.
2. American Academy of Dermatology: ten things physicians and patients should question. Choosing Wisely. https://www.aad.org/scientificsessions/sam2019/SessionDetails.aspx?id=12730. Last updated July 9, 2019. Accessed July 26, 2019.