Mepolizumab rescue therapy for acute pneumonitis secondary to DRESS

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome represents a severe adverse drug reaction driven by eosinophilia. Treatment is focused on withdrawal of medication, supportive care and immunosuppression such as high-dose corticosteroid therapy. Here we report a 56-year-old male patient who initially presented with breathlessness and eosinophilia, subsequent development of respiratory failure and admission to ITU for non-invasive ventilation. The patient continued to deteriorate despite high-dose prednisolone and methylprednisolone. Other causes of hypereosinophilia were normal. He was diagnosed with DRESS syndrome secondary to pregabalin and was treated with subcutaneous mepolizumab. We observed the rapid resolution of eosinophilia and clinical improvement; the patient was discharged home within a month of administration. This represents the successful use of mepolizumab in the acute setting of pulmonary failure secondary to DRESS. A similar approach could be adopted in other acute conditions with refractory eosinophilic inflammation where standard steroid therapy has failed.