Hypersensitivity reactions
Regarding immediate hypersensitivity reactions (IHRs), urticaria is the most frequent manifestation (68); furthermore, anaphylaxis can occur (69). Concerning NIHRs, MPE is described to occur independently (70) or only in presence of a concurrent infection (71). Azithromycin has been implicated in contact dermatitis in occupational (72) and non-occupational settings (73). Cases of fixed drug eruption (FDE) (74), AGEP (75) and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) (76), SJS (77,78), leukocytoclastic vasculitis (79), and hypersensitivity myocarditis (80) were reported.
Diagnosis is complex as skin testing is not validated, presenting discrepancies in non-irritating dilutions for SPT and intradermal test (IDT) (81,82). For NIHRs, positive responses to patch tests (PTs) were described (72). In addition, no validatedin vitro tests are available (83). Oral DPT remains as the gold standard for diagnosis (84). A successful desensitization protocol was reported in a case of mast cell activation syndrome (85).