Woolly hair nevus: a rare entity.

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.

INTRODUCTION

Woolly hair nevus is a rare condition, characterized by unruly and tightly coiled hair, which is not genetically determined. It may be localized to one or several areas of the scalp. We report a case of woolly hair nevus in a child.

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. Examination 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

A well-circumscribed patch of tightly coiled woolly hair

Figure 2

HPE of scalp showing normal hair follicle and appendages

DISCUSSION

Woolly hair is characterized by tightly coiled hair occurring over the entire scalp or part of it in an individual of non-African origin. Hutchinson et al. have classified woolly hair types as follows: 1. Hereditary woolly hair, 2. Familial woolly hair, 3. Symmetrical circumscribed allotrichia 4. Woolly hair nevus.[1]

The term woolly hair nevus was first described and coined by Dr. Fred Wise in 1927. It is a nevoid condition characterized by a circumscribed patch of unruly and curled hair with an altered texture. Both sexes are equally affected.[2] At birth, the hair may be normal as in our child. It becomes coarser with age giving an unsightly appearance. This condition may be associated with melanocytic or epidermal nevi[3], mongolian spots[4] elsewhere on the skin. Ocular defects like persistent pupillary membrane,[25] retinal defects,[6] and precocious puberty have also been associated.[7] Electron microscopic findings include twisting of hair shaft and abnormal cuticle formation.[8]

Woolly hair nevus is not associated with cardiac abnormalities as in Carvajal or Naxos disease in which desmoplakin and plakoglobin mutations are known to occur, respectively.[9] Our patient presented with an isolated woolly hair nevus without any associations, which has been reported very rarely. However, this patient must be followed up regularly to detect any cardiac defects which may present later.[10]