Background Immune dysregulation, polyendocrinopathy, enteropathy, X‐linked (IPEX) syndrome is a rare disorder characterized by neonatal autoimmune enteropathy, diabetes and thyroiditis, food allergies and skin rash. IPEX syndrome is caused by mutations in FOXP3, a master control gene of regulatory T cells (Tregs), resulting in absent or dysfunctional Tregs. Data in the literature are scarce and the cutaneous manifestations are rarely depicted.

Objectives To evaluate the frequency and characteristics of cutaneous manifestations found in IPEX.

Methods Retrospective single‐centre study of a case series of IPEX. Patients’ data were retrieved from medical files and numerous parameters concerning general and cutaneous characteristics of the disease were recorded.

Results Ten children with IPEX were studied. Cutaneous involvement was present in seven of 10 chidren; age at onset was 0–4 months, median 1·5. All patients presented with atopic dermatitis (AD). Three presented more psoriasiform lesions. Eczema was severe; most affected areas were lower limbs, trunk and face. Pruritus was present in four of seven, and painful fissurary cheilitis in four of seven. Hyper‐IgE was found in seven of 10 and hypereosinophilia in five of 10. Skin biopsies showed eczematiform or psoriasiform features. Affected patients were improved by dermocorticoids; no clear improvement was obtained with immunosuppressive regimens. Other features were urticaria secondary to food allergies and staphylococcal sepsis, mostly Staphylococcus aureus and catheter related.

Conclusions AD seems to be a frequent finding in IPEX syndrome, which is characterized by Treg anomalies. This hints to a possible role of Tregs in AD, which is then discussed in this study.