[Ichtyosiform erythroderma revealing a severe combined immunodeficiency]. / Érythrodermie ichtyosiforme révélant un déficit immunitaire combiné sévère.

BACKGROUND: Severe combined immunodeficiency (SCID) is a the most severe form of primary immunodeficiency and is highly heterogeneous. We report an atypical form of SCID revealed by exfoliative erythroderma. PATIENTS AND METHODS: A 3-month-old boy, born to consanguineous parents, was admitted to the dermatology department with exfoliative erythroderma associated with eczematous patches and alopecia of the scalp, eyelashes, and eyebrows, but with no lymphadenopathy or hepatosplenomegaly. He displayed chronic diarrhea and recurrent infection since birth. A complete blood count showed marked leukocytosis with eosinophilia and lymphocytosis. These clinical and biological findings improved partly with topical steroids. The patient no longer had erythroderma and showed regrowth of hair, eyelashes and eyebrows. The subsequent CBC showed less marked eosinophilia with mild lymphopenia and no leukocytosis. Immunoglobulin levels were undetectable. Primary immunodeficiency was discussed. Immunological investigations concluded on a diagnosis of T-B-NK+ SCID. Mutation analysis revealed a homozygous c.1338C>G (pCys446Trp) mutation in the RAG2 gene. Hematopoietic stem cell transplantation is planned in the near future. CONCLUSION: This case illustrates atypical T-B-NK+ SCID revealed by severe exfoliative erythroderma in a 3-month-old boy with RAG2 gene mutation. Neonatal erythroderma must be considered a warning sign of primary immunodeficiency requiring immediate immunological phenotyping as well as genetic testing for a definitive diagnosis.

[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.

[Pityriasis rubra pilaris]. / Pityriasis rubra pilaire.

Pityriasis rubra pilaris is a rare heterogeneous dermatosis associating three clinical signs to different degrees: follicular corneal papules, reddish-orange palmoplantar keratoderma and erythematosquamous lesions that may in some cases be very extensive, interspersed with patches of healthy skin. The aetiology is unclear, and in most cases, the trigger factors consist of trauma or infection, probably in subjects with an existing predisposition. In other cases, the condition is associated with immunological disorders or, in familial cases, genetic keratinisation abnormalities similar to ichthyosis. Given the widely varying signs, several classifications have been proposed, based on clinical criteria and outcomes. The outcome varies in accordance with the clinical forms involved. Therapeutic approaches are poorly qualified and there have been no clinical trials due to the rarity of the disease. However, the best results appear to have been obtained using oral retinoids, with second-line therapy comprising methotrexate and cyclosporine. The landscape of therapeutic strategy seems to be changing with the advent of new anti-tumour necrosis factor and anti-interleukin-12/23 antibodies.

[T-cell prolymphocytic leukemia: potential diagnostic pitfalls]. / Leucémie prolymphocytaire T : un piège diagnostique à connaître.

BACKGROUND: Sezary syndrome (SS) presents clinically as erythroderma, which may be pigmented, and pruritic, associated with peripheral lymphadenopathies. Erythroderma may also occur in a broad range of reactive and malignant conditions including T-cell prolymphocytic leukemia (T-PLL). We report a case initially diagnosed as SS but ultimately diagnosed as T-PLL based upon skin involvement. CASE REPORT: A 70-year-old man was referred by his hematologist for management of SS. Physical examination revealed lymphadenopathies and mild diffuse erythema without infiltration. His WBC count was elevated at 8.3 G/L. A peripheral blood smear showed Sezary-like cells. Flow cytometry of peripheral blood revealed prolymphocytic T-cells staining positively for CD2, CD3, CD4 and CD7. Cytogenetic studies showed chromosomal abnormalities in terms of number and structure with missing chromosomes 6 and13, as well as deletion of chromosome 17. Finally, a diagnosis of T-PLL was made. Pentostatin was initiated pending treatment with alemtuzumab, but the patient's overall condition deteriorated rapidly and he died 10 days later. DISCUSSION: Diagnosis of LPLT is based upon a number of factors. In the case presented herein, the clinically atypical nature of the skin lesions prompted the dermatologist to review the diagnosis. The morphology of the circulating T-lymphocytes and their immunologic and phenotypic characteristics finally ruled out the diagnosis of Sezary syndrome, while their association with compatible cytogenetic anomalies enabled a diagnosis of prolymphocytic leukemia to be made instead. CONCLUSION: Prolymphocytic leukemia involves complex differential diagnosis with regard to Sezary syndrome, posing potential pitfalls for hematologists and dermatologists.