A Case of Woolly Hair Nevus Associated with Pigmentary Demarcation Lines and Heterochromia Iridis: Coincidence or a New Association?

We report a case of woolly hair nevus with pigmentary demarcation lines and heterochromia iridis. Woolly hair nevus is a rare abnormality of the scalp hair characterized by the patch of hair, which is curlier and light colored than the rest of the scalp hair. Association of woolly hair nevus with some other ectodermal defects effecting skin and eyes has been reported before. Here, woolly hair nevus associated with demarcation lines and heterochromia iridis, to our knowledge, have not been previously reported.

INTRODUCTION

Woolly hair nevus is a rare abnormality of the scalp hair that appears since birth or during first 2 years, characterized by the patch of hair, which is curlier and light colored than the rest of the scalp hair.[123] Here, we present a case of woolly hair nevus with ipsilateral pigmented demarcation lines and heterochromia iridis.

CASE REPORT

A 5-year-old girl with a patch of kinky hair in the right parietal region, which had been present since the age of 4 months and different colored eyes since birth referred to our clinic [Figure 1]. The underlying scalp was normal. The affected hair appeared smaller in diameter and lighter than the normal hair color and no structural hair abnormalities were detected under the light microscope. She had slightly hyperpigmented linear lesions mostly marked on the anterolateral of the right arm with midline pectoral and abdominal extension [Figure 2]. The right eye was diffusely brown, and the left was green [Figure 3]. No ophthalmologic, cardiac, neurological or skeletal abnormalities were observed. Nails and teeth were normal. The patient was diagnosed with a woolly hair nevus of the right parietal scalp associated pigmented demarcation lines and heterochromia iridis.

Figure 1

Woolly hair nevus. Curled woolly hair on the left parietal region

Figure 2

Pigmentary demarcation lines on the right anterolateral arm extending to the right pectoral and abdominal region

Figure 3

Heterochromia iridis, right eye has brown eye color and left eye has green

DISCUSSION

Hutchinson et al. classified woolly hair into three categories as hereditary woolly hair, familial woolly hair, and woolly hair nevus.[4] Woolly hair nevus was divided into three groups by Post which is (1) with no associated scalp disorders or hairless skin, (2) with associated linear verrucous epidermal nevus, (3) acquired, which has been termed “acquired progressive kinking of scalp hair.”[5]

Pigmentary demarcation lines (PDL) are transition lines between the areas of darker and lighter or normal pigmentation with eight different types described (A–H).[6] Type A is an anterolateral aspect of upper arm with variable transpectoral extension and the type C is in median or paramedian vertical lines on the chest with midline abdominal extension.[6] In our subject, the coexistence of type A and C is observed.[6] PDL is thought to coincide with the distribution of cutaneous nerve innervations.[6] Krivo proposed that these lines are related to pigmentary mosaicism.[7]

Heterochromia iridis is usually a sporadic and benign condition and may be affected by genetic and multiple physiological factors.[8] Melanin is the main chromophore of the human iris and is the most important factor that determines the color of the irides.[8] Heterochromia iridis is related with some dermatologic diseases such as Waardenburg syndrome, hypomelanosis of Ito, and linear scleroderma.[9] Circumscribed hypopigmentation along with Waardenburg syndrome, café au lait macule, and also hyperpigmented patch without any systemic disease are other mentioned pigmentary anomalies associated with heterochromia iridis.[91011]

Skin, hair, and eyes are all ectodermal origin. The association of woolly hair nevus with some other ectodermal defects has been reported before suggesting the term woolly hair nevus syndrome.[3] Whether the coexistence of heterochromia iridis with woolly hair nevus and demarcation lines is just coincidental or a true association remains unclear. This association, to our knowledge, has not been previously reported. The patients with the woolly hair nevus are suggested to be evaluated for the other systemic or ectodermal defects that may accompany this lesion and long-term follow-up is needed.

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Conflicts of interest

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