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C.
Hair Analysis: Light microscopic exam of hair revealed shaft in a ball and socket configuration known as "bamboo hair" or trichorrhexis invaginata (Fig.C) which is characteristic of Netherton Syndrome.
Discussion: Netherton Syndrome is a rare autsomal recessive disorder characterized by abnormal keratinization and erythroderma, atopy, and hair defects. Ichthyosis linearis circumflexa is the cutaneous manifestation of Netherton Syndrome presenting as generalized hyperkeratosis and serpiginouw erythematous plaques with double edged scale at the borders. Patients usually present within the first 10 days of birth with erythroderma and development is complicated by failure to thrive. Laboratory abnormalities that may be observed include elevated serum IgE and aminoaciduria. Hypernatremia may occur due to dehydration through defective skin.
Trichorrhexis invaginata is the characteristic hair defect that presents under light or electron microscopic examination as "bamboo hair". This is a result of abnormal cornification of the internal root sheath. Identification of this defect may not be obvious as sometimes only 20% of the hair is affected. Other less frequent or characteristic follicular defects include trichorrhexis nodosa (shaft knotting) and pili torti (shaft coiling and twisting).
Atopic diathesis is another associated finding and the patient may present with urticaria, asthma, atopic dermatitis, or angioneurotic edema after eating nuts. Pruritus from atopic dermatitis may lead to scratching and lichenification particularly at the antecubital fossae.
Although there is no cure for Netherton Syndrome, the life span for most patients is normal. Treatment is supportive and aimed at alleviation of symptoms. Since the cutaneous defect disrupts thermal, immunologic , and lipid barriers, the goal is to improve it with generous and frequent application of emollients and keratolytics. Symptomatic relief of dermatitis and pruritus along with treatment of cutaneous infections with topical or oral antibotics, as indicated, are also important.
REFERENCES:
Mallory SB and Krafachik BR. What syndrome is this? Netgerton Syndrome. Ped. Derm. 1992, 9:157-160.
Green SL and Muller SA. Netherton's syndrome: Report of a case and review of the literature. JAAD 1985, 13:2(part 2):329-336.
DiGiovanna J. Icthyosiform Dermatoses. In: Fitzpatrick's Dermatology In General Medicine 5th Edition. McGraw-Hill 1999. pp 595-596.
My thanks to Drs. Jaeyoung Yoon and Susan Mallory for their help in the preparation of this case.
