Chronic paronychia is a condition that results in nail dystrophy that usually extends across the entire breadth of the involved nail. It is caused when there is disruption of the proximal nail fold/ cuticle resulting in a space under the free edge of the nail fold, which creates a chronic wet area which is an ideal environment for yeast, often of the candidal persuasion.
The way to distinguish this from, say, Beau’s lines is to look at the proximal nail fold/ cuticle unit to see if it is intact. Next, look at the character of the transverse grooves. If they are irregular and kind of ragged looking, it is usually a result of chronic paronychia. If, on the other hand, it is a smooth, even curvilinear line across the nail plate, it is usually a Beau’s line. Remember: Beau’s lines are a result of a physiologic stress of one sort or another; it is a reflection of a systemic issue, not a local one. It is the same process (slowing of the growth of the matrix) which in the hair also leads to telogen effluvium. In fact, if I am trying to work someone up for telogen effluvium, the first thing I do is look at their nails. The best place to find Beau’s lines is the fourth (ring) fingernail for reasons that are completely unclear to me, but chronic paronychia can be on any nail.
The reason I put this picture in is because chronic paronychia was discussed in the blog a couple of days ago under habit tic deformity. NOBODY should have missed this question!!