Língua villosa nigra in an infant

A 5-week-old male infant, with no significant family history and a term pregnancy (birth weight of 3510 grams (P50)) adequately monitored, was taken to the emergency department (ED) due to a change in the color of the tongue first noticed a week earlier. The patient was exclusively breastfed and was supplemented with adequate dose of vitamin D beginning in the first month of life. Physical examination revealed a blackish discoloration of the posterior 2/3 of the tongue´s dorsal area (Figure 1), that did not disappear with the rubbing of the spatula. No other abnormality in the oral cavity was present including any signs of trauma. He was treated with miconazole gel for the previous week without any changes in the condition. He had a normal length and weight evolution (percentile 50) with no feeding difficulties. Vaccines were according to the national immunization schedule. There were no other accompanying symptoms namely respiratory, nor vomiting, diarrhea, constipation, and no history of herbal products ingestion.

Figure 1. Lingua villosa nigra.


What is the Diagnosis?