Woolly Hair with Systematized Epidermal Nevus.

Woolly hair is a hair shaft disorder characterized by fine and tightly curled hair. Woolly hair could be syndromic (associated with systemic disease) or non-syndromic (not associated with any systemic disease). Woolly hair is described in association with many skin, dental, ophthalmic and cardiac anomalies but association of woolly hair with bilateral systematized epidermal nevus described in our case is first of its kind.

What was known?

Woolly hair is a hair shaft disorder which is reported in isolation or with multiple associated skin, cardiac, dental and ophthalmic abnormalities. Localized variant of woolly hair (Woolly hair nevus) is frequently described in association with a linear epidermal nevus.

Introduction

Woolly is tightly coiled, fine and often hypopigmented hair. It was first described by Gossage in 1907 and later classified by Hutchinson et al., in 1974 into woolly hair nevus, autosomal dominant hereditary woolly hair and autosomal recessive familial woolly hair.[1] Generalized woolly hair can occur in isolation or it can have syndromic association. Association of generalized woolly hair is also described with cutaneous anomalies, such as keratosis pilaris or palmoplantar keratoderma, and extracutaneous anomalies, especially cardiac or of senses. Localized variant of woolly hair (Woolly hair nevus) is frequently described in association with a linear epidermal nevus; however, no such association is described with generalized woolly hair. We describe the first case of generalized woolly hair in association with bilateral systematized epidermal nevus.

Case Report

A 6-year-old boy presented with abnormally curly scalp hairs and patches of darker skin over whole body, most evident over neck, trunk and arms. According to history given by parents, the child was born full term of non-consanguineous marriage with dark linear and whorled patches over his whole body including scalp and without hairs over scalp. When scalp hairs first grew, they were abnormally curly and slow growing.

On examination the child had whorled and streaked linear hyperpigmented verrucous plaques affecting the whole body including scalp. Scalp hairs were coarse, lusterless, dry and tightly curled [Figure 1]. Seborrhoeic dermatitis was also present over scalp. Nail and teeth were normal. Investigations revealed normal hematological and biochemical parameters. Light microscopy of scalp hair revealed thin and hypopigmented hair [Figure 2]. There was no evidence of trichorrhexis nodosa. X-ray chest, electrocardiogram and echocardiography were normal. The child had normal IQ without any eye problem. The patient had a younger sister who had absolutely normal hair and skin. Also, parents of the patient did not have similar complaint.

Figure 1

Clinical image of the patient showing woolly hair and systemised epidermal nevus (a, b). Close view of neck (c, d) and head (e) better shows the findings

Figure 2

Hair microscopy-arrow showing hypopigmented and thin woolly hair lying alongside a normal hair of a child of same age

Histopathology of skin lesion [Figure 3] revealed papillated epidermal hyperplasia, with hypergranulosis and hyperkeratosis composed of compact ortho and parakeratosis consistent with epidermal nevus.

Figure 3

Histopathology (Hematoxylene and Eosin stain, ×40 magnification) showing papillated epidermal hyperplasia, with hypergranulosis and hyperkeratosis composed of compact ortho and parakeratosis

Discussion

The term “woolly hair” has been derived due to coiling and crimping of hair similar to sheep wool.[23] Woolly hair is a rare congenital structural abnormality of the scalp hair without increased fragility, characterized by tightly coiled hair involving part or the entire scalp occurring in a non-negroid individual.[13] Woolly hair grows at a normal or slower rate as compared to normal hair and are different from curly hairs of Negros because the curls are separable in Negro hairs but not in woolly hairs.[34] In 1974, Hutchinson et al. further classified woolly hair into a localized variant (woolly hair nevus) and two generalized variants, including autosomal dominant (AD) hereditary woolly hair and autosomal recessive (AR) familial woolly hair. Later on diffuse partial woolly hair has also been described as a separate entity.[1]

Epidermal nevi are nests of epidermal cells which are noted at birth or within the first year as a thin plaque or linear tan patch often along Blaschko lines. Extensive epidermal nevi, often in unilateral distribution, are called as systematized epidermal nevi. Histologically, epidermal nevi show hyperkeratosis and papillomatosis. Epidermal nevus can be an isolated finding or it can show syndromic/nonsyndromic association with other cutaneous/extracutaneous lesions.[5]

Localized variant of woolly hair (woolly hair nevus) is frequently found in association with a linear epidermal nevus of focal or systematized distribution.[6]

Generalized variants of woolly hair (involving the whole scalp) are also described in syndromic/nonsyndromic association with other lesions.[4] Notable syndromic association of woolly hair is found in autosomal recessive Nexos disease and Carvajal disease caused by mutation of desmosomal proteins plakoglobin and desmoplakin respectively. Both diseases are characterized by triad of generalized woolly hair, palmoplantar keratoderma, and cardiomyopathy (right ventricular in Naxos disease, left ventricular in Carvajal disease).[4] Therefore, with the diagnosis of generalized woolly hair, a thorough evaluation of all organ systems, especially of the heart, must be conducted.

The absence of family history of similar disorder, with diffuse scalp involvement, in our patient probably suggests a hereditary form of woolly hair resulting due to de novo mutation. Associated bilateral systematized epidermal nevus was also seen in our case. To the best of our knowledge, our case is the first reported case of such type of association.

What is new?

Our case is of hereditary wooly hair in association with bilateral systematized epidermal nevus which is not described in literature previously.