Sweet Syndrome Triggered by a Change in Inhalation Therapy: A Rare Drug-Induced Presentation
A 55-year-old woman with a medical history of hypertension and chronic obstructive pulmonary disease (COPD) presented to her primary care physician with sudden-onset painful skin lesions affecting her face and neck, accompanied by low-grade fever and general discomfort. Her chronic conditions had been well controlled with enalapril for hypertension and formoterol as maintenance therapy for COPD.
Two days prior to symptom onset, her inhalation regimen had been modified to a combined bronchodilator therapy containing indacaterol and glycopyrronium. She reported no recent infections, no exposure to new cosmetics or skincare products, no dietary changes, and no history of allergies or autoimmune disease. The rapid progression of symptoms prompted urgent referral to dermatology.
On examination, the patient exhibited multiple tender, erythematous plaques involving the cheeks, forehead, and cervical region. The lesions were well-defined, raised, and associated with significant pain. Given the temporal relationship between medication change and symptom development, clinicians suspected a possible drug-induced reaction.
The new inhaled medication was immediately discontinued, and oral corticosteroid therapy was initiated. Laboratory investigations revealed leukocytosis with marked neutrophilia, supporting an inflammatory or immune-mediated process. Serologic testing for infectious, autoimmune, and connective tissue diseases returned negative.
Within 48 hours of corticosteroid treatment, the patient experienced significant clinical improvement. The fever resolved, pain diminished, and the skin lesions began to regress. A punch biopsy of the affected area confirmed the diagnosis of Sweet syndrome, also known as acute febrile neutrophilic dermatosis.
Sweet syndrome is a rare inflammatory condition characterized by the abrupt appearance of painful, erythematous plaques or nodules, accompanied by fever and systemic symptoms. Histologically, it is defined by dense infiltration of mature neutrophils in the dermis without evidence of vasculitis. The condition is more commonly observed in middle-aged women and may occur in association with infections, malignancies—particularly hematologic cancers—autoimmune diseases, pregnancy, or medications.
Drug-induced Sweet syndrome accounts for a smaller subset of cases, with reported triggers including granulocyte colony-stimulating factor, antibiotics, antiepileptics, and certain chemotherapeutic agents. However, to date, there have been no widely documented cases linking inhaled bronchodilators such as indacaterol or glycopyrronium to this condition, making this presentation particularly notable.
Several alternative diagnoses were carefully considered. Urticaria was excluded due to the fixed, painful nature of the lesions and lack of migratory behavior. Contact dermatitis was unlikely in the absence of new topical exposures. Toxicoderma and cutaneous lupus were also ruled out based on clinical findings, laboratory results, and histopathology.
This case underscores the importance of maintaining a broad differential diagnosis when evaluating acute dermatologic reactions, particularly following medication changes. While inhaled therapies are generally regarded as safe and well tolerated, clinicians should remain alert to the possibility of rare systemic adverse effects.
Early recognition of Sweet syndrome is critical, as it often responds rapidly to systemic corticosteroids and may signal underlying systemic disease. Patients diagnosed with this condition should undergo appropriate evaluation to exclude malignancies, autoimmune disorders, and other potential triggers.
For primary care providers, this case highlights the value of prompt referral to dermatology and collaboration across specialties when managing atypical drug reactions. Awareness of rare dermatologic syndromes can prevent delays in treatment, reduce patient morbidity, and facilitate early detection of potentially serious associated conditions.
In conclusion, although exceedingly rare, Sweet syndrome should be considered in patients presenting with acute painful erythematous lesions and systemic symptoms following medication changes—even when the medication involved is an inhaled bronchodilator. Continued documentation of such cases will help expand clinical knowledge and improve future diagnostic accuracy.
admin