The prevalence of atopy was investigated in 20 patients with Sézary syndrome (SS), 20 patients with plaque phase mycosis fungoides (MF), 9 patients with primary cutaneous marginal zone lymphoma (pcMZL) and 8 patients with primary cutaneous follicle center lymphoma (pcFCL) with the Phadiatop multi‐allergen test. The relationship among serologic atopy, IgE reactivity against Staphyloccocal enterotoxin superantigens, and serum total IgE (IgE‐t) levels and their prognostic implications in SS was investigated. Phadiatop test was positive in 45%, 15%, 33% and 0% of samples of SS, MF, pcMZL and pcFCL, respectively. IgE‐t levels were also increased in SS, pcMZL and marginally MF. No correlation was found with patients’ history of atopic disorders. Staphylococcal superantigen‐specific IgE ≥ 0.35 kUa/L, most often against toxic shock syndrome toxin‐1, was detected in 40% of Sézary samples followed by MF (20%). In the absence of serologic atopy (negative Phadiatop test), IgE‐t levels for patients with SS and MF were not significantly higher than controls whereas the levels for pcMZL remained high. Furthermore, even with a negative Phadiatop test, IgE‐t values were higher in sera of patients with SSAg‐IgE ≥ 0.35 kUa/L vis‐à‐vis < 0.35 kUa/L across all diagnostic categories including controls albeit the difference was statistically significant only for SS. The presence of specific IgE antibodies ≥ 0.35 kUa/L, IgE‐t > 122 kU/L or eosinophils > 500/µL had no impact on survival of patients with SS. These results indicate that a pathogenic link may exist between an atopic diathesis and development of SS and possibly pcMZL