2019 Volume 62 Issue 7 Pages 406-411
A 96-year old woman receiving linagliptin and insulin glargine for type 2 diabetes mellitus at a nearby hospital developed bullous pemphigoid and visited our hospital. She exhibited plasma glucose elevation, but her HbA1c level was only 3.7 %. Based on the detection of macrocytic normochromic anemia, indirect bilirubin-dominant hyperbilirubinemia, reticulocytosis, hypohaptoglobinemia, and false-positive occult blood in urine, hemolytic anemia was suspected to have caused the low HbA1c level. Suspecting the involvement of diaphenylsulfone (DDS), a treatment for bullous pemphigoid, we discontinued this drug. This resulted in the rapid improvement of hemolysis and HbA1c elevation, strongly suggesting that the clinical findings were due to DDS administration. Reports on DDS-induced hemolytic anemia and false low HbA1c levels are rare. However, DDS may be used as a treatment for pemphigoid, with an increased risk of development with the use of dipeptidyl peptidase-4 inhibitors and sodium glucose cotransporter 2 inhibitors, which are widely used in Japan. In addition, hemolytic anemia develops at a lower dose of DDS in Japanese patients than in patients of other nationalities. Therefore, DDS use requires further caution.
