[Erythroderma revealing IPEX syndrome]. / Érythrodermie révélatrice d'un syndrome IPEX.

BACKGROUND: Primary immunodeficiencies are rare and frequently life-threatening conditions in the first year of life. They may present with isolated skin manifestations and the absence of other clinical signs may delay diagnosis and management of the disease. Herein we describe a case of IPEX syndrome (Immune dysregulation, Polyendocrinopathy, Enteropathy, X-linked syndrome) that illustrates this situation. PATIENTS AND METHODS: A 2.5-month-old boy was seen with a psoriasiform eruption. Despite applications of topical steroids, skin lesions progressed to severe exfoliative ichtyosiform erythroderma. A skin biopsy showed keratinocyte necrosis with a dense, epidermotropic, lymphocytic CD8+ infiltrate. The infant presented increased serum IgE and eosinophilia. He developed an enteropathy with severe and profuse diarrhea, septicemia and hypovolemic shock that led to sudden cardiac arrest. DNA analysis revealed a mutation in the FOXP3 gene, confirming IPEX syndrome. A favorable outcome was achieved following allogeneic bone marrow transplant. DISCUSSION: IPEX syndrome is characterized by early secretory enteropathy with profuse diarrhea, dermatitis and diabetes mellitus. Onset usually occurs within the first weeks or months of life, and the natural course of the disease is often lethal. Cutaneous manifestations appear to be mostly eczematiform, psoriasiform or ichthyosiform. These may be the first sign of the disease and a common inflammatory skin disorder may be wrongly diagnosed. The severity of the lesions and their limited response to topical steroids should alert the clinician. CONCLUSION: The early onset of severe cutaneous manifestations with persistent lesions and poor response to topical steroids should lead to an early skin biopsy. If histopathological changes show a cytotoxic lymphocytic infiltrate with keratinocyte necrosis, a diagnosis of primary immunodeficiency must be considered enabling rapid intitation of specific management.