• BACKGROUND
    • Involvement of the nail is quite common in psoriasis and at times may be the sole diagnostic clue. However, the histopathology of nail psoriasis has not been adequately evaluated. A confirmation of the diagnosis is required in cases suspected to have nail psoriasis in order to plan long-term therapy.
  • OBJECTIVES
    • To assess the diagnostic significance and safety profile of nail biopsy in cases with nail psoriasis.
  • METHODS
    • Clinical and mycological features were studied in 42 patients with nail psoriasis. Of these, 22 patients gave consent for nail biopsies to be taken and the histopathological changes were assessed.
  • RESULTS
    • Males were affected more commonly (57%) with a peak incidence in the age group of 10-20 years (29%). Distal onycholysis, discoloration of nail plate, subungual hyperkeratosis and fine nail pitting were the predominant clinical features. In the 22 biopsies done, hyperkeratosis with parakeratosis (91%) was found to be the most common and hypergranulosis was the least common histological finding (36%). Clinicohistological correlation was possible only in 55% cases. Periodic acid-Schiff (PAS) staining was done for all biopsies.
  • CONCLUSIONS
    • Histopathological examination of nails is a valuable diagnostic aid, especially in the absence of skin lesions. Examination of the PAS-stained sections is necessary before making a histological diagnosis of nail psoriasis because onychomycosis and psoriasis may show similar histology.