[A case report of delayed drug hypersensitivity reaction caused by inhalation and nasal spray of budesonide].

Inhaled and intranasal corticosteroids are widely used in the management of allergic respiratory diseases. Delayed drug hypersensitivity reactions to budesonide are a rare adverse drug reaction characterized by non-immunoglobulin E (IgE)-mediated clinical manifestations, including localized or systemic contact dermatitis, mucosal edema, and paradoxical worsening of pre-existing symptoms. However, such reactions are often underdiagnosed due to atypical presentations. Here, we reported a patient with bronchial asthma and allergic rhinitis who developed a fever accompanied by lip and nasal swelling 12 hours after using a budesonide/formoterol powder inhaler and a budesonide nasal spray. The diagnosis of budesonide-induced delayed hypersensitivity was confirmed through skin prick testing, intradermal testing, patch testing, and drug provocation testing. This case underscores the role of integrating multiple diagnostic modalities in evaluating suspected drug hypersensitivity reactions. Our findings highlighted the need for clinical vigilance regarding the potential sensitizing effects of inhaled/intranasal corticosteroids and offered valuable insights into the individualized diagnosis and management of patients with similar allergic profiles.