Acute Generalized Exanthematous Pustulosis Induced by Hyaluronic Acid Knee Injection: A Case Report.

Acute generalized exanthematous pustulosis is a severe cutaneous adverse reaction characterized by the rapid onset of nonfollicular, sterile pustules on an erythematous base, typically accompanied by fever (≥38 °C), neutrophilia (7.0 × 10⁹/L), and characteristic histopathological features. This case report presents the first documented instance of acute generalized exanthematous pustulosis after hyaluronic acid viscosupplementation. A 61-year-old female developed a pruritic, erythematous rash that rapidly evolved into generalized erythroderma with systemic manifestations after receiving intra-articular hyaluronic acid injections for knee osteoarthritis. Initial physical examination and diagnostic workup, including biopsy and blood tests, were performed to exclude other differential diagnoses such as generalized pustular psoriasis, subcorneal pustular dermatosis, and immunoglobulin A pemphigus. The temporal association with hyaluronic acid injections and the patient's positive response to treatment with systemic corticosteroids and antihistamines supported the definitive diagnosis of drug-induced acute generalized exanthematous pustulosis. The patient was managed with the withdrawal of the offending agent, and supportive care was provided. She did not require rehabilitation and experienced no adverse events during the recovery period. Follow-up visits confirmed the absence of recurrence and complete resolution of symptoms, with no lasting sequelae. This case underscores the importance of recognizing acute generalized exanthematous pustulosis' acute manifestations and potential triggers, even with treatments generally considered safe. ED personnel, including advanced practice registered nurses and other clinicians, must include acute generalized exanthematous pustulosis in their differential diagnoses of severe cutaneous disorders to initiate prompt and appropriate management. The development of atrial fibrillation during hospitalization in this patient raises questions about the systemic effects of acute generalized exanthematous pustulosis, suggesting an area for further research. Early detection and treatment of acute generalized exanthematous pustulosis are crucial for favorable outcomes, illustrating the vital role ED personnel play in managing this condition. Awareness of rare triggers such as hyaluronic acid is essential for preventing and effectively treating such severe adverse reactions.