Irritant contact dermatitis following extracorporeal shockwave therapy: a case report

Extracorporeal shockwave therapy (ESWT) has been widely used in the treatment of various musculoskeletal disorders with remarkable efficacy, with no relevant severe complications being reported. In this study, we report a rare case of acute irritant contact dermatitis following ESWT with serious skin damage, which has never been previously reported. A 42-year-old male patient with osteonecrosis of the femoral head (ONFH) was subjected to two sessions of ESWT. In the first session of low-energy ESWT (0.15 mJ/mm2, 3 Hz, and a total of 2,000 impulses), no local or systematic adverse reactions occurred. Three months later, he was subjected to a second session of high-energy ESWT (0.28 mJ/mm2, 4 Hz, and a total of 2,000 impulses). However, on the second day, the patient presented with itching and painful erythema and blisters on the local skin of the hip. Based on these manifestations and the results of patch testing, the patient was diagnosed with irritant contact dermatitis and treated by an oral antihistamine combined with external calamine lotions. The skin lesions began to develop exudate from erosion and scabs had gradually formed with treatment, and finally dry scabs fell off with no scar left. This is the first reported irritant contact dermatitis after ESWT. Although bone pathologies should be treated with high energy, patients should be informed of this potential rare complication.