Hypereosinophilic syndrome (HES) is a rare, heterogeneous group of systemic diseases characterized by sustained overproduction of eosinophils leading to variable end-organ damage. The skin is affected in 45–60% of patients and may be of diagnostic and prognostic value. In 1975, three criteria were suggested for the diagnosis of HES: (i) blood eosinophilia of > 1.5 × 109/L present for > 6 months, (ii) no apparent cause for the hypereosinophilia, and (iii) signs of end-organ dysfunction. We present a patient with hypereosinophilia in whom a delay in diagnosing HES occurred, partly due to his atopic constitution. However, atopy is not associated with such high or longstanding eosinophilia.