Image Letter

Fox Tail Like Furry Appearance in a Case of Black Hairy Tongue

Author Affiliation(s)

Case Presentation

A 22-year-old Indian male, non-smoker, a known case of non-Hodgkin B-cell lymphoma, subtype diffuse large B-cell lymphoma, developed dark discoloration of the dorsum of the tongue, with dysgeusia, metallic taste, and halitosis two weeks after undergoing an autologous stem cell transplant and being started on prophylactic Tab Penicillin G and Tab Acyclovir [ 1 ] . The discoloration was insidious in onset and progressed over 20 days to involve the majority of the anterior two thirds of the tongue. Examination of oral mucosa revealed a brownish to black-colored furry tongue predominantly involving the anterior two-thirds of the tongue anterior to the circumvallate papillae, with relative sparing of the tip and lateral borders ( Figure 1A ). No significant pigmentation was noted at any other site. The KOH mount revealed no fungal hyphae, and the culture revealed no growth. Dermoscopy was performed which revealed characteristic findings (described below). The patient was advised to practice regular tongue brushing and maintain proper oral hygiene, which led to regression of elongated papillae and resolution of symptoms in 2 weeks.

Teaching Point

Dermoscopic examination revealed yellowish-brown and brownish-black furry projections (elongated filiform papillae) resembling ‘Fox tail’ (green arrow), white globular areas (red arrow) over a pinkish background (black arrow) resembling rose petals. A distinct color variation was also appreciated in individual filiform papillae, with the base being a lighter shade than the tip (blue arrow) ( Figure 1B ).


  1. Black hairy tongue after allogeneic stem cell transplantation: an unrecognized cutaneous presentation of graft-versushost disease Akay BN, Sanli H, Topcuoglu P, Zincircioğlu G, Gurgan C, Heper AO. Transplant Proc.2010;42(10):4603-4607. CrossRef PubMed
  2. “Sea Anemone” Appearance in Dermoscopy of Black Hairy Tongue Sil A, Panigrahi A. Indian Dermatol Online J.2021;14(4):580-581. CrossRef PubMed

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