Ichthyosis hystrix.

The present report describes the condition in a three day old male child with bilateral ,linear, hyperpigmented and hyperkeratotic verrucous plaques and patchy alopecia over scalpe without any nail and skeletal abnormalities. It was suggestive of ichthyosis hystrix type of epidermal nevus,and is being reported in view of the rarity of this condition.

INTRODUCTION

Ichthyosis hystrix the nomenclature comes from the Greek word and condition was first described in England in early 18th century. The term ichthyosis hystrix is used to describe several rare skin disorders in the ichthyosis family of skin disorders characterized by massive hyperkeratosis with an appearance like spiny scales. The term has also been employed to describe localized and linear warty epidermal nevi sometimes associated with mental retardation, seizures or skeletal anomalies. Alopecia and hair and nail abnormalities as well as inner ear deafness were also seen in these patients.

CASE REPORT

A 3-day-old full-term male, born by cesarean section out of non-consanguineous marriage, was referred to us from the Obstetrics and Gynaecology department with complaints of extensive verrucous hyperpigmented lesions.

A detailed general examination revealed an extensive systematized epidermal nevus over the scalp, forehead, the entire trunk (both anteriorly and posteriorly) and both upper and lower limbs. The nevus was more prominent over the left half of anterior trunk [Figure 1], extending along midline of genitalia. Posteriorly it was almost symmetrical [Figure 2]. In all sites, nevi followed the lines of Blaschko. Over the scalp [Figure 3], it followed a fronto-occipital linear distribution and in the involved areas, there was complete loss of hair. The palms and soles were spared, so also most part of the face. Nails were normal. In the lower limbs, in addition to the nevus, there were unilateral hyperpigmented [Figure 1] macular patches encircling right upper thigh and complete left thigh, sparing a band-like zone.

Figure 1

Hyperpigmented, verrucous patches on front following lines of Blaschko

Figure 2

Similar lesions over back

Figure 3

Lesions over scalp, resulting in linear bands of alopecia

On physical examination, we could not observe any defects, especially in skeletal or central nervous systems. Routine laboratory examination including complete blood count, urine analysis, liver function test and chest X-ray were all within normal limits. The parents did not permit a biopsy.

Based on the above constellation of clinical features (history, typical morphology, and generalized, roughly bilaterally symmetrical involvement), a diagnosis of ichthyosis hystrix type of epidermal nevus (systematized epidermal nevus) was made.

The name ichthyosis hystrix comes from the Greek words ichthyos meaning fish and hystrix meaning porcupine. It is a descriptive name for a heterogeneous group of keratinization disorders sharing similar features of massive, spiky or verrucous hyperkeratosis clinically and epidermolytic hyperkeratosis histologically.

The condition was first described in the Lambert family in England in the early 18th century. This term is also used to refer to a type of epidermal nevus with extensive bilateral distribution.[1]

Since in 1902 Brocq[2] first reported ichthyosis hystrix as a atypical form of congenital bullous ichthyosiform erythroderma, many authors described it by different names including nevus verrucosus, systematized epidermal nevi, and epidermolytic hyperkeratosis. In 1980, Gianotti[3] classified it as a localized form of congenital epidermolytic hyperkeratosis.

The term systematized epidermal nevus is used for lesions that are bilateral and excessive; similarity to the lesions of ichthyosis is emphasized in the term ichthyosis hystrix.[4]

Histological examination of the epidermis shows acanthosis, papillomatosis, and severe orthokeratotic hyperkeratosis, with frequent binucleate cells.[5] Study of three generations of the families of Curth and Macklin with ichthyosis identified a mutation in the variable tail domain (V2) of the keratin-1 gene.[6] Solomon and Esterly[7] provided a detailed account of the spectrum of epidermal nevi seen in the epidermal nevus syndrome. They described seven types of lesions. The majority of patients had nevus unius lateralis; 20% of patients had ichthyosis hystrix.

In 1978, Basler et al.[8] first described a case of ichthyosis hystrix that was not associated with any other defects. Subsequently, a few authors reported similar cases of ichthyosis hystrix without involvement of other systems. Our case also did not have any systemic abnormality.

Clinical expression varies, even within families, from palmoplantar keratoderma to a severe, generalized involvement. There can be widespread, patchy, thick, gray-brown hyperkeratosis, most marked on extensor surface of the arms and legs. However, in contrast to epidermolytic hyperkeratosis, blistering does not occur.

A condition that closely resembles ichthyosis hystrix with a melanocytic nevus is phacomatosis pigmentokeratotica. It is characterized by the coexistence of an epidermal nevus following the Blaschko's lines that usually shows sebaceous differentiation with a large speckled lentiginous nevus, typically arranged in a chequerboard pattern. This syndrome is an example of cutaneous mosaicism that is thought to be related to twin spotting phenomenon. It differs from ichthyosis hystrix by the absence of a systematized nevus.

There is no specific treatment for ichthyosis hystrix. Major treatment consists of symptomatic therapy for complications and cosmetic purposes. Topical retinoids, usually tretinoin, may be beneficial. A good result with etretinate is reported by many authors,[910] which can be planned once the baby attains the right age.