Photoonycholysis.

BACKGROUND/
PURPOSE: Photoonycholysis may be seen as a part of Segal's triad, photosensitivity followed by discoloration of the nails and onycholysis. But the latter may also appear, independently, in the absence of photosensitive reaction elsewhere.
METHODS: Photoonycholysis may result from drug intake, porphyria cutanea tarda, erythropoietic porphyria, erythropoietic protoporphyria, variegate porphyria and pseudoporphyria. Rarely, spontaneous photoonycholysis may be observed.
RESULTS: Four distinct subtypes have been recorded without relationship between the responsible drugs and the different clinical varieties of photoonycholysis. Primary photohemorrhage can occur; it can also be associated with polydactylous photoonycholysis type III.
CONCLUSION: The inability to reproduce photoonycholysis experimentally should be emphasized.