Muehrcke's lines

Muehrcke's lines, or leukonychia striata, are changes in the fingernail that may be a sign of an underlying medical disorder or condition.

Common causes
The appearance of Meuhrcke's lines is nonspecific, but they are often associated with decreased protein synthesis, which may occur during periods of metabolic stress (e.g., after chemotherapy) and in hypoalbuminemic states such as the nephrotic syndrome.

An example of Muehrcke's Lines in the context of chemotherapy was published in the New England Journal of Medicine in 2007.

Complete Differential Diagnosis of the Causes of Muehrke's Lines (alphabetical):

 * Chemotherapy
 * Nephrotic syndrome

Physical examination
Muehrcke's lines are white lines that extend all the way across the nail and lie parallel to the lunula (half moon). In contrast to Beau's lines, they are not grooved. The lines are actually in the vascular nail bed underneath the nail plate, and as such, they do not move with nail growth. Meuhrcke's lines disappear when pressure is placed over the nail, blanching the underlying nail bed.