title: Azathioprine hypersensitivity: report of two cases and review of the literature.
abstract: Azathioprine (AZA) is a widely-used drug in the treatment of different diseases such as vasculitis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel diseases and in renal transplantation. Side effects of AZA can be classified as toxic, mainly dose related (myelosuppression and hepatotoxicity) and idiosyncratic, mainly dose independent. While the toxic effects are common and well documented, the hypersensitivity reactions are rare and it is not often easy to distinguish them from systemic sepsis or disease recurrence. We report two cases of AZA hypersensitivity occurring in patients with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis each mimicking a vasculitis relapse or a septic complication of immunosuppression, as well as a review of the literature.
authors.affiliation: Unit of Nephrology and Dialysis, Center of Clinical Immunology and Rheumatology, San Carlo Borromeo Hospital, Via Pio Secondo 3, 20153 Milan, Italy. renato.sinico@oscb.sined.net
authors.forename: Renato A
authors.initials: RA
authors.lastname: Sinico
authors.forename: Ettore
authors.initials: E
authors.lastname: Sabadini
authors.forename: Sabrina
authors.initials: S
authors.lastname: Borlandelli
authors.forename: Pablo
authors.initials: P
authors.lastname: Cosci
authors.forename: Luca
authors.initials: L
authors.lastname: Di Toma
authors.forename: Enrico
authors.initials: E
authors.lastname: Imbasciati
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology; D001379:Azathioprine / Q000009:adverse effects* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004342:Drug Hypersensitivity / Q000175:diagnosis*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D008875:Middle Aged; D035583:Rare Diseases; D018570:Risk Assessment; D012720:Severity of Illness Index; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000188:drug therapy* / Q000276:immunology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D007166:Immunosuppressive Agents; D001379:Azathioprine