|Year : 2014 | Volume
| Issue : 1 | Page : 27-29
Type A woolly hair nevus
Jayakar Thomas, B Ragavi Sindhu, Dinesh Kumar Devaraj, Parimalam Kumar
Department of Dermatology, Sree Balaji Medical College, Chromepet, Chennai, Tamil Nadu, India
|Date of Web Publication||2-May-2014|
135, East Mada Church Road, Royapuram, Chennai - 600 013, Tamil Nadu
Source of Support: None, Conflict of Interest: None
We present a 5-year-old girl with Type A woolly hair nevus. This is a rare non-hereditary focal condition characterized by unruly and tightly coiled hair. It may be associated with epidermal or melanocytic nevus. Children with woolly hair must be examined completely and monitored regularly to rule out cardiofaciocutaneous and Noonan syndrome.
Keywords: Kinky hair, woolly hair, woolly hair nevus
|How to cite this article:|
Thomas J, Sindhu B R, Devaraj DK, Kumar P. Type A woolly hair nevus. Indian J Paediatr Dermatol 2014;15:27-9
| Introduction|| |
Woolly hair nevus is a rare non-hereditary focal condition characterized by unruly and tightly coiled hair. It can appear in childhood or adolescence and may be associated with epidermal or melanocytic nevus. Patients presenting with woolly hair must be examined completely to rule out cardiofaciocutaneous and Noonan syndrome. We present a 5-year-old with Type A woolly hair nevus.
| Case report|| |
A 5-year-old girl child presented with abnormal patch of hair since 2 years of age. Her parents noticed a single patch of curling and coiling of hair along with altered texture over the left side of scalp. Her parents felt the patch to be unruly and unsightly and hence attempted repeated tonsuring. In spite of this, the patch of hair remained the same. Birth and development history of the child was normal. Her family members did not have similar complaints. On examination, we noticed a solitary circumscribed patch of size 6 × 4 cm located over the left frontoparietal region of scalp. The hair over the patch had an altered texture, was lighter in color, thinner, tightly coiled, and curled giving an unkempt appearance [Figure 1]. The skin over the patch was apparently normal. Examinations of rest of the scalp, teeth, and nails were also normal. There was no evidence of palmoplantar keratoderma and evidence of any epidermal nevus elsewhere. Ophthalmic and cardiac evaluation did not reveal any abnormality. There was no evidence of precocious puberty. Based on the above findings, we arrived at a diagnosis of localized woolly hair nevus. Hair microscopic examination showed non-specific features. Scalp biopsy revealed normal hair follicles and appendages [Figure 2]. Routine hemogram, serum biochemistry, electrocardiogram, and echocardiogram were normal.
|Figure 1: The hair over the patch showing an altered texture, thinner, tightly coiled, and curled giving an unkempt appearance|
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| Discussion|| |
The term Woolly hair nevus was first used by Dr Fred Wise in April 1927. The case reports were about two 5-year-old girls whose families were unrelated and both of whom showed light woolly hair on one portion of the scalp, while the rest of the hair was straight and brown.  Woolly hair nevus is a rare, non-genetically determined condition in which unruly and tightly curled hair is localized on one or several areas of the scalp. The abnormal hair may be slightly lighter in color. 
Woolly hair nevus is a subdivision under Woolly hair syndrome. Woolly hair syndrome is a group of disorders involving structural defects in hair shaft without any increase in fragility. Woolly hair was classified by Hutchison et al.  as follows
- Hereditary woolly hair (Autosomal Dominant)
- Familial woolly hair (Autosomal Recessive)
- Symmetrical circumscribed allotrichia
- Woolly hair nevus.
Woolly hair nevus occurs sporadically affecting both the sexes equally. Most often the condition manifests from birth or within the first 2 years of life. There could be up to five circumscribed areas with woolly hair in an individual.  The cause of the condition is unknown.
Woolly hair nevus was divided into three types by post: 
- That without any changes in the glabrous skin or scalp
- That accompanied by a linear nevus of the skin
- That acquired in adult life, in which scalp hair assumes the characteristics of pubic hair. The third group has been classified as acquired progressive kinking of the hair. 
Our case belonged to Type A, as above, without any changes in the glabrous skin or scalp.
Woolly hair nevus accompanied by ipsilateral linear epidermal nevus is common and seen in nearly 50% of the cases.  In woolly hair, dermatoscopy shows the image of hair shafts resembling a crawling snake with short wave cycles.  A variety of structural changes are observed on microscopy. The hair on cross-section is elliptical along with loss of cuticle and trichorhexis nodosa features. The diameter of the hair shaft diameter is reduced and could exhibit tapering, irregular twisting along the long axis, and cortical vacuolation. An uncommon presentation could be the appearance of triangular cross-sections with longitudinal grooves. The anagen to telogen ratio remains normal along with the normal hair growth rate. Histopathological examination is normal except for curved anagen hair. 
Though the diagnosis of woolly hair nevus is clinical there may be confusion with pili torti, uncombable hair syndrome or loose anagen syndrome, and drug-induced kinking of the hair.
In addition to linear epidermal nevus, woolly hair nevus can be associated with nevus comedonicus, Cafe-au-lait spots, hypopigmented patches, hemangiomas, multiple nevi, (both congenital and acquired), precocious puberty,  and ocular defects like persistent pupillary membrane and loss of retinal pigment epithelium. ,, Cardiac abnormalities such as arrhythmogenic right ventricular dysplasia or cardiomyopathy (ARVD/C) are known to occur with woolly hair and palmoplantar keratoderma. This recessively inherited syndrome is known as Naxos disease. 
In most of the cases there could improvement in the hair with age; however, there are few effective treatment options for woolly hair nevus. Surgical excision of the affected area followed by reconstruction with flaps could be attempted in certain cases. 
| References|| |
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[Figure 1], [Figure 2]