Sharma A, Sharma V (2014) Hyperpigmentation of the Tongue due to Interferon. JSM Gastroenterol Hepatol 2(4): 1030.

A 25 year old male presented with recent onset blackish pigmentation of his tongue (Figure 1)

Figure 1: Blackish pigmentation of the tongue.

which he had noted for past 2 weeks. He had been previously evaluated for incidentally detected elevated transaminase levels which were found to be due to chronic hepatitis C infection. He was found to harbour infection with genotype 3 and high HCV RNA levels. The patient had been initiated on therapy with pegylated interferon α 2-a 180 µg/week with daily ribavirin (800mg) 10 weeks back and had achieved an undetectable level at 4 weeks (rapid virological response). The patient was assured about the benign nature of the hyperpigmentation and agreed to continue treatment.

Hyperpigmentation of tongue can result from number of causes including systemic diseases like Addison’s disease, local lesions like melanoma and oral lichen planus or can be physiological [1]. Drugs like interferon, minocycline or bismuth subsalicylate can also cause hyperpigmentation of tongue and drug history must form an important part of evaluation of such patients [2]. The tongue hyperpigmentation with interferon is usually asymptomatic, more common in dark-skinned individuals and may be associated with concurrent gum, and oral mucosal involvement. Upregulation of receptors of melanocyte stimulating hormone on melanocytes is believed to be responsible [3]. The hyperpigmentation resolves slowly after interferon is stopped and there is no need to halt therapy [1,2]. 

1. Bachmeyer C, Pellen JC. Tongue hyperpigmentation during hepatitis C treatment. CMAJ. 2012; 184: 1498.
2. Gurguta C, Kauer C, Bergholz U, Formann E, Steindl-Munda P, Ferenci P. Tongue and skin hyperpigmentation during PEG-interferon-alpha/ribavirin therapy in dark-skinned non-Caucasian patients with chronic hepatitis C. Am J Gastroenterol. 2006; 101: 197-198.
3. Karabay O, Goksugur N, Ogutlu A. Tongue hyperpigmentation during interferon therapy. J Dermatol. 2011; 38: 290-291.