Abstract Onychia and paronychia caused and sustained by fusospirochetal organisms in a white boy, aged 17 years, are described, seemingly the first such observation in the American literature. The condition lasted for two years with slow but definite progress, without lymphangitis or lymphadenitis. Local application and intravenous administration of neoarsphenamine were without success. Surgical removal of the nails of the affected fingers brought about prompt healing. The necessity of prompt bacterioscopic examination of the discharge is urgently advocated in every case of this disease.