Can You Identify This Tongue Condition?

A 77-year-old woman was admitted to the sub-acute unit for medical rehabilitation. The patient was blind secondary to metastatic brain disease from a carcinoma of the paranasal sinus. She received chemotherapy, which was complicated by severe anorexia.

Per the daughter's report, the patient had not eaten any solid food—only nutrition shakes—for a month. The patient's medications included vitamin B12, folic acid, and trazodone. Patient did not have any reported drug allergies.

The patient's vital signs were normal, but patient appeared chronically sick. Clinical examination was notable for nasal discharge and a yellow, dark brown, coated tongue (Figure). 

What are you looking at here?

(Answer and discussion on next page)

Answer: Black Tongue

This picture is typical of what is called black tongue. The surface of the tongue is not smooth. Anatomically, its surface showed scattered minute tissue elevations called papillae. The histology of the tongue reveals that its surface is overlaid by a constantly shedding epithelium, which limits the projection of the papillae over the lingual surface. Solid food, by its abrasive effect on the epithelium, can also prevent the overgrowth of the papillae. 

Black tongue may have a variety of causes, including malnutrition, certain medications (mostly Pepto-Bismol), antibiotics, smoking, chemotherapy, and radiation therapy of the neck. 

This patient’s black tongue can be mostly attributed to the lack of solid food, as well as decreased lingual movement with concomitant poor oral hygiene. There is overgrowth of the lingual papillae, including proliferation of pigment-producing microorganisms.

Despite the frightening appearance of black tongue, it is in fact a benign condition and can be treated by improving the solid food intake for patients not eating and improving oral hygiene. Unfortunately, our patient became critically ill and expired while under treatment.