Metronidazole-induced linear immunoglobulin A disease in a patient suffering from ulcerative colitis: a case report and focused review of the literature

Linear immunoglobulin (Ig) A disease (LAD) is a rare autoimmune blistering dermatosis caused by linear deposition of IgA1 along the dermoepidermal junction of skin and mucosae. It can affect both children and adults. Although idiopathic in most cases, it can also be associated with infections, malignancies, or drug administration. Among medications, antibiotics are most commonly responsible, particularly vancomycin. We report the case of a 51-year-old female patient who developed mucocutaneous LAD after oral metronidazole administration, which was confirmed by histopathological examination and direct immunofluorescence of one of the bullous lesions. Lesions rapidly cleared after metronidazole discontinuation and a short course of oral methylprednisolone and dapsone. To our knowledge, this is the third reported case of metronidazole-induced LAD and the first in which metronidazole was not administered in combination with other antibiotics such as ceftriaxone.