Nail changes can reveal major systemic disease, from cirrhosis and endocarditis to melanoma., Splinter hemorrhages + fever murmur should make you think of infective endocarditis., Single Noticed a dark streak on your nail? It could be melanonychia a condition where pigmentation appears in the nail plate, often as a brown or black line. While it's commonly Melanonychia NailKnowledge Melanonychia: Clues for Diagnosis and the Importance of Histology Next Steps in Dermatology