Case 1:

During a routine skin examination, periungual erythema and increased curvature of the nail plate are noted in a 78-year-old man. The patient has emphysema and a smoking history of more than 50 pack-years. Currently, he requires oxygen for regular daily activity.

What do you suspect is the cause of the nail deformity?

(Answer on next page.)

Clubbing of the nails can be congenital or acquired. The latter form is associated with both neoplastic and inflammatory pulmonary diseases in most patients and with cardiovascular abnormalities in nearly all the rest. Other systemic illnesses—such as inflammatory bowel disease, HIV infection, cirrhosis, hypertrophic osteoarthropathy, and hyperthyroidism—are rare causes of clubbing.

In affected patients, the distal digits are enlarged and swollen. The nail plate is curved, and the angle between the proximal nail fold and the nail plate (Lovibond angle) is greater than 180 degrees. To confirm the increased angle, position the nails of both index fingers close together. In patients without clubbing, there is a diamond-shaped space between the nails. This space is markedly decreased or completely absent in patients without clubbing.

There is no effective treatment. Management of the underlying systemic illness may not correct the nail abnormalities.

(Case and photograph courtesy of Steven Q. Wang, MD.)

Are The Marks On This Man's Nails Related to Hepatitis C?

A 43-year-old man with hepatitis C virus infection and cirrhosis complains of dry, itchy skin. He also has paired, transverse white bands on all his fingernails.

To what do you attribute the nail discoloration?

(Answer on next page.)

Answer: Muehrcke lines associated with hypoalbuminemia and cirrhosis

The white bands on this patient’s nails are Muehrcke lines—a relatively uncommon finding associated with a low albumin level and cirrhosis. The white bands are horizontally paired, separated by areas of normal nail color, and arranged parallel to the lunula. Muehrcke lines are a good clue to the presence of hypo­albuminemia; this patient’s albumin level was 2.1 g/dL.

The differential diagnosis includes leukonychia (congenital and acquired) and Mees lines (caused by arsenic poisoning). These abnormalities are in the nail plate, while Muehrcke lines represent edema in the nail bed.

Treatment of the nails is unnecessary. Bear in mind that amelioration of the underlying systemic illness may not change the nail color.

This patient’s low albumin level is chronic, and he is being monitored closely by a hepatologist.

(Case and photographs courtesy of Steven Q. Wang, MD.)