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Hair loss and hair shaft disorders
Published in Giuseppe Micali, Francesco Lacarrubba, Dermatoscopy in Clinical Practice, 2018
Trichorrhexis invaginata is a very rare hair shaft disorder that characterizes Netherton disease, an autosomal recessive genodermatosis which combines ichthyosis, trichorrhexis invaginata and atopic dermatitis. Hair fragility and breakage cause alopecia, which is more severe in scalp areas exposed to friction; it frequently affects eyelashes and eyebrows that may present the abnormality even when the scalp hair, which improves with age, appears normal.
Hair dysplasias
Published in Pierre Bouhanna, Eric Bouhanna, The Alopecias, 2015
Juan Ferrando, L. Alheli Niebla, Gerardo A. Moreno-Arias
Trichorrhexis invaginata includes both a ballooning distortion of the hair shaft as well as a chaliced deformation of the proximal hair shaft. This characteristic alteration gives the hair shaft a bamboo cane aspect; therefore, this hair dysplasia is also known as “bamboo hair,” a specific hair anomaly that is considered a marker for Netherton disease.
Clinical Aspects and Differential Diagnosis of Atopic Dermatitis
Published in Donald Rudikoff, Steven R. Cohen, Noah Scheinfeld, Atopic Dermatitis and Eczematous Disorders, 2014
Donald Rudikoff, Diana Lee, Steven R. Cohen
Hair-shaft defects and atopic manifestations, such as elevated IgE levels, food allergy, allergic rhinitis, asthma, and eosinophilia can occur concomitantly in Netherton syndrome. The range of hair and scalp abnormalities includes short, brittle hairs, scaly scalp, and a pathognomonic defect termed ‘trichorrhexis invaginata.’ Descriptively, trichorrhexis invaginata occurs when the proximal portion of the hair overlaps the distal portion, creating a likeness to intussusception of the bowel or the stalk of bamboo (known as bamboo hair) (Burk et al. 2008) (Fig 3.62). Dermatoscopic examination of the hair shaft can facilitate early diagnosis (Fig 3.63). Powell (2000) has observed that the density of nodes per unit length of hair is 10 times greater in eyebrow hairs than in scalp hairs; eyebrow hairs should be cut, not plucked. Therefore, examining the eyebrows will offer the highest yield of bamboo hairs. Children with Netherton syndrome typically have sparse hair (Fig 3.64) but this can be seen as well in some patients with AD. Other hair defects such as trichorrhexis nodosa and pili torti have also been described in these patients. Generalized erythroderma in the first months postpartum can make the diagnosis of Netherton syndrome an enormous challenge. However, within the first year of life, classic lesions of ichthyosis linearis circumflexa appear as distinctive, migratory, polycyclic, erythematous plaques with a double-edged scale (Fig 3.65 and see Fig 3.61b).
Advances in understanding of Netherton syndrome and therapeutic implications
Published in Expert Opinion on Orphan Drugs, 2020
Evgeniya Petrova, Alain Hovnanian
Under light microscopy, hairs show a pathognomonic abnormality known as trichorrhexis invaginata (TI), or bamboo hair, resulting from the invagination of the distal part of the hair shaft into the cup formed by the proximal hair shaft Figure 2. Although highly specific for NS, TI is not always present and does not involve all hairs. Alopecia can be diffuse or localized with areas of broken hair surrounded by long unbroken, but abnormal hairs. In rare cases, patients have no alopecia but long hair of normal appearance, with or, infrequently, without TI.