Drug-induced photo-onycholysis. Three subtypes identified in a study of 15 cases.
We have studied 15 patients with photo-onycholysis induced by tetracyclines, psoralens, or fluoroquinolones. Three distinct clinical subtypes of onycholysis were seen. Type I showed a half-moon-shaped separation that was concave distally. Type II had a circular notch opened distally and shaped as if the distal nail plate had acted as a convex lens. In type III the changes were located in the central part of the nail bed with no connection to the margins. Ultraviolet (UV) irradiation of normal fingernails with various wavelengths showed that 3% to 20% of the irradiation could penetrate the nail. The different patterns of photodamage might be caused by the nail acting as a lens. Less protection by lack of melanin and absence of sebum and stratum granulosum may favor penetration of UV irradiation and explain why the skin was not always affected.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000890:Anti-Infective Agents / Q000009:adverse effects; D002648:Child; D004318:Doxycycline / Q000009:adverse effects; D003875:Drug Eruptions / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009260:Nail Diseases / Q000139:chemically induced*; D009262:Nails / Q000187:drug effects; D009643:Norfloxacin / Q000009:adverse effects / Q000031:analogs & derivatives; D015242:Ofloxacin; D010078:Oxazines / Q000009:adverse effects; D011701:PUVA Therapy / Q000009:adverse effects; D015366:Pefloxacin; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D013752:Tetracycline / Q000009:adverse effects; D014307:Trioxsalen / Q000009:adverse effects; D014466:Ultraviolet Rays / Q000009:adverse effects
D000890:Anti-Infective Agents; D010078:Oxazines; D015366:Pefloxacin; D015242:Ofloxacin; D013752:Tetracycline; D009643:Norfloxacin; D004318:Doxycycline; D014307:Trioxsalen