Abstract
Hyper-immunoglobulin E (IgE) syndrome (HIES) is an immunodeficiency syndrome characterized by atopic dermatitis, recurrent skin abscesses, and sinopulmonary infections with elevated serum IgE. In addition, patients also present with other skeletal and non-immune symptoms. We present a six-year-old boy with severe atopic dermatitis, multiple food allergies, mild asthma, and recurrent sinopulmonary infections, who presented to the ER with left ankle pain, fever, and inability to bear weight. Physical examination showed generalized eczematous lesions, significant left ankle ecchymosis, swelling, and tenderness. Investigations were pertinent for leukocytosis with neutrophilia and markedly elevated IgE levels with normal IgM, IgG, and IgA levels. HIES genetic panel was negative. MRI with contrast of the affected limb was consistent with osteomyelitis that responded to antimicrobial therapy. This case highlights a diagnostic challenge for allergists and clinicians when evaluating patients with severe atopic dermatitis, recurrent infections, and markedly elevated serum IgE without positive genetic results.