D3.370 - Three cases of erdosteine-induced delayed drug hypersensitivity

Background

Erdosteine is a mucolytic agent used for a variety of respiratory diseases and is generally considered safe. Only a few cases of allergic reactions to erdosteine have been reported. However, we have occasionally experienced cases of drug allergy associated with erdosteine in clinical practice. Here, we describe three cases of erdosteine-induced delayed allergic reactions.

Methods

Three patients diagnosed with erdosteine-induced drug allergy at our hospital were enrolled. Culprit drugs were identified using skin tests, including patch test and intradermal test with delayed reading, and drug provocation test.

Results

The first case was admitted for skin rashes two days after taking medications, including erdosteine, for upper respiratory infection. The rashes were maculopapular lesions with some non-blanchable purpura and were diagnosed as cutaneous vasculitis based on positive immunofluorescence staining for immunoglobulins and complements on skin biopsy. The culprit was identified as erdosteine based on positive oral provocation test. The second case presented for evaluation to identify the culprit drug causing skin rashes. He had experienced five episodes of rashes occurring 1-7 days after taking medications for upper respiratory infections. The rashes were oval or round with well-demarcated margins, recurred at the same sites, and resolved within 1-2 weeks with residual pigmentation, which was diagnosed as fixed drug eruptions. Erdosteine had been included among the medications taken during all five episodes. The culprit was identified as erdosteine based on positive patch test. The third case was admitted for fever and skin rashes seven weeks after starting asthma medications, including erdosteine and doxofylline. Hypereosinophilia, hepatitis, pneumonia, and splenomegaly were observed, and bronchoalveolar lavages revealed eosinophilia. Drug reaction with eosinophilia and systemic symptoms (DRESS) was diagnosed. The culprit was identified as both erdosteine and doxofylline based on patch test and intradermal test with delayed reading.

Conclusions

Based on our cases, erdosteine can induce cutaneous vasculitis, fixed drug eruption, and DRESS. Therefore, erdosteine should be considered a potential culprit drug in patients with suspected drug hypersensitivity reactions.