Black Hairy Tongue After Allogeneic Stem Cell Transplantation: An Unrecognized Cutaneous Presentation of Graft-Versus-Host Disease

The study described black hairy tongue (BHT) as an underrecognized manifestation of cutaneous graft-versus-host disease (GVHD) in patients who underwent allogeneic stem cell transplantation (allo-SCT). Among 93 evaluated patients, 15 (16.1%) developed BHT, often alongside other GVHD symptoms. The study emphasized the importance of histopathologic evaluation for BHT in the posttransplantation period due to its potential prognostic implications for GVHD. The patient group included 4 females and 11 males, with a mean age of 34.7 years. The findings suggested that BHT could serve as a precursor or indicator of GVHD, highlighting the need for careful monitoring by physicians.