A 49-year-old man presented for his annual physical examination and had concerns about a nail abnormality. His medical history was significant for chronic pain disorder managed with oxycodone, and he was a 20-pack-year smoker. He ambulated with the assistance of a cane. There was no history of trauma to the nail. The abnormality had developed in the past 3 months.

Physical examination revealed clubbing of all fingernails and thin, hyperpigmented, nonblanchable, vertical streaks in the distal half of the right thumbnail (Figure 1). The patient had a regular heart rate and rhythm with no murmurs, rubs, or gallops, and his lungs were bilaterally clear to auscultation. He was afebrile.

QUESTION

Based on the patient's history and physical examination, which one of the following is the most likely diagnosis?

• A. Melanonychia striata.

• B. Splinter hemorrhage.

• C. Subungual hematoma.

• D. Subungual melanoma.

DISCUSSION

The answer is B: splinter hemorrhage. Splinter hemorrhages present as nonblanchable, thin, linear, reddish-brown to black longitudinal streaks within the nail bed. The streaks typically do not span the entire nail bed. They may occur on one or more nails. Cases that are limited to a single nail typically have benign causes, most often trauma. Some cases are idiopathic. The prevalence of splinter hemorrhages is increased in manual workers, individuals who wear acrylic fingernails, and those who use a cane.¹