During my recent deployment to Afghanistan, a 31-year-old man came into our aid station with a bilateral thumbnail deformity that he’d had for several weeks. He was concerned about a thumbnail infection and wanted to discuss antifungal treatment. His history was unremarkable, and he said he had no nail fold infections or other skin conditions. He was taking doxycycline for malaria prophylaxis. He also mentioned that he had recently started working as a military intelligence officer, putting in 18-hour days.
His exam revealed sharp, closely spaced horizontal grooves on both of his thumbnails (FIGURE). His nails had no hyperkeratotic debris or pitting. His nail folds appeared hypopigmented with scaling, but they were nontender to palpation. His other fingernails were normal in appearance. The remainder of the skin exam was unremarkable.
FIGURE
Horizontal grooves on both thumbnails
What is your diagnosis?
How would you manage this condition?