In this early morning session, Boni E. Elewski, MD, gave the audience pearls for diagnosing and managing difficult nail diseases. Dr Elewski’s first tip was about recognizing nail lichen planus. Lichen planus of the nails can present with fissuring, nail plate thinning, angel wing deformity, and dorsal pterygium. Once dorsal pterygium has occurred, the disease is considered end-stage and untreatable, highlighting the importance of early recognition and treatment. Treatment options include oral or intralesional corticosteroids, retinoids, and JAK inhibitors. Case reports have demonstrated improvement in nail lichen planus with baricitinib, abrocitinib, and tofacitinib.

Dr Elewski’s next tip was on recognizing nail psoriasis. Five percent of patients with psoriasis have only nail disease. Nail psoriasis is common on fingernails, and signs include pitting, onycholysis with red border, and oil spots. Onycholysis with subungual debris on the toenails is more likely to be onychomycosis. Nail psoriasis is associated with higher rates of scalp psoriasis, inverse psoriasis, and psoriatic arthritis. For treatment, Dr Elewski informed the audience that 4 meta-analyses have concluded that ixekizumab, an IL-17A inhibitor, has the highest rate of nail clearance. Dr Elewski also discussed topical and intralesional treatments for localized nail disease.

Moving on to a common nail problem that is becoming more difficult to treat, Dr Elewski discussed terbinafine-resistant onychomycosis. Certain trichophyton species are demonstrating increased rates of terbinafine resistance, up to 80% for T. indotineae. Trichophyton rubrum species have a 1% to 2% resistance rate. Dr Elewski reviewed common antifungal dosing regimens including terbinafine 250-mg once daily for 3 to 6 months, fluconazole 300-mg once weekly for 16 weeks, itraconazole 200-mg once daily for 3 to 6 months, and topical efinaconazole 10% solution applied around and under the nail until clear. For treatment-resistant onychomycosis, Dr Elewski recommended oral itraconazole or terbinafine 500-mg daily.

To conclude, Dr Elewski reviewed etiologies of a “black nail.” Sudden-onset melanonychia is likely to be a subungual hematoma, while a green-black nail can be caused by a pseudomonas and Candida coinfection. Medications are common causes of acquired melanonychia, and Dr Elewski gave a great tip on attempting to scrape discoloration off in these cases. Dr Elewski closed by reminding the audience of the ABCDEFs of longitudinal melanonychia that should raise suspicion for nail plate melanoma: Age >50 years, Brown-black band >3-mm wide, Change, Digit being thumb or great toe, Extension to proximal nail fold, and Family history.