Netherton syndrome: A rare genodermatosis.

Sir,

Netherton syndrome (NS) is a rare autosomal recessive hereditary ichthyosiform disease. The classical triad of clinical features comprises an ichthyosiform dermatosis, hair shaft abnormalities, and atopic diathesis.[1] Usually, a generalized erythroderma is present at birth or soon after. Later, skin manifestations can present either as ichthyosis linearis circumflexa (ILC), characterized by polycyclic and serpiginous, erythematous plaques with a characteristic migratory, double-edged scale at the margins, or less frequently as congenital ichthyosiform erythroderma (CIE). Two-thirds of patients have various atopic manifestations and elevated immunoglobulin class E (IgE).[2] Hair shaft abnormalities include trichorrhexis invaginata, pili torti and/or trichorrhexis nodosa.[34]

An 8-year-old boy, reported with generalized scaly lesions since infancy. The boy was the first issue of nonconsanguineous parents. Erythema, desquamation, and scaling started in the first year of life and lesions typical of ILC began to appear at the age of 3 year. Personal history of atopic like eczema, allergic rhinitis, and recurrent urticaria was present. The child was of average built with widespread erythematous, serpiginous, annular or polycyclic, scaly eruptions with double-edged scales at the periphery of the lesions distributed more on extremities than on trunk [Figure 1]. The lesions were continuously changing their patterns, size, and shape with a migratory nature, involuting in a week or two without any scarring, atrophy, or pigmentary changes. Skin was dry due to hypohidrosis. Multiple erythematous and pruritic papules were present on trunk but not in typical distribution of atopic dermatitis. Flexural lichenification was not evident. Scalp hair, eyebrows, and eyelashes were sparse, rough, brittle, lusterless, and slow growing [Figures 2 and 3]. However, light microscopy could not show bamboo hair (trichorrhexis invaginata). Nails were normal in texture and growth. Allergic rhinitis, chronic blepharitis, and ectropion were present [Figure 3]. Complete hematological checkup showed mild anemia and peripheral eosinophilia. Histopathological examination could not be done due to nonconsent of parents. On the bases of ichthyosis linearis circumflexa, hair anomaly and atopic manifestations, a diagnosis of Netherton syndrome was made.

Figure 1

Gyrate lesions with double-edged scaling

Figure 2

Sparse, rough, brittle, and lusterless scalp hair

Figure 3

Chronic blephritis and ectropion

NS is caused by mutation in serine protease inhibitor, Kazal type 5 gene (SPINK5), which is located on the long arm of Chromosome 5. Hair shaft abnormalities manifested as trichorrhexis invaginata, pili torti and/or trichorrhexis nodosa.[4] This may not be detectable at birth, and may disappear with age.[5]

Atopy is usually manifested as atopic dermatitis-like skin lesions, angioedema, allergic rhinitis, asthma, urticaria, food allergy, peripheral eosinophilia, and elevated IgE. In many patients, skin lesions are not clinically eczematous, and they do not respond to appropriate eczema therapy.[6]

Gastrointestinal involvement in the form of dermopathic enteropathy with villous atrophy and diarrhea may lead to poor weight gaining in early childhood. Other associations include aminoaciduria, recurrent infections, mental and neurological retardation and impaired cellular immunity. Histopathologic examination is not specific and may show the features of hyperkeratosis, psoriasis, and atopic dermatitis.[5]

The therapy with topical steroids, tacrolimus, tars, emollients, PUVA, and oral vitamin A derivatives is not satisfactory and risk of systemic toxicity is high because of increased percutaneous absorption.[5]