Lichen striatus with onychodystrophy in an infant.

Lichen striatus with nail involvement is rare and is often unnoticed. Nail changes are often nonspecific but they are usually localized to one portion of the nail. Also single nail involvement and presence of skin lesions near the nail are often noticed. We report the case of an infant with lichen striatus and nail involvement.

INTRODUCTION

Lichen striatus (LS) is linear papular dermatoses that primarily occurs in children between four months and 15 years of age and is relatively rare in adults.[12] Nail involvement in lichen striatus is uncommon with only 30 cases reported in the literature since 1972 [Table 1], the youngest being a 10 month old infant.[13] We herein report the case of a 9-month-old infant with LS and onychodystrophy.

Table 1

Review of cases of lichen striatus with nail involvement in literature

CASE REPORT

A 9-month-old female infant was referred for evaluation of asymptomatic linear eruption over the right lower limb and acquired nail dystrophy of the corresponding big toe. The skin eruption had started a month earlier and the nail changes developed two weeks later. Dermatologic examination revealed erythematous flat topped papules with fine scaling present below the right knee, which coalesced into a linear band and extending down the extensor aspect of the leg, reaching the dorsum of the foot and the great toe. The lateral side of right great toe nail showed thinning of the nail plate, splitting, longitudinal ridging, and nail bed hyperkeratosis [Figure 1]. Other body sites were not involved and all investigational analysis provided normal parameters. A 3 mm punch biopsy from one of the skin lesions revealed hyperkeratosis, focal parakeratosis, and a few necrotic keratinocytes in the epidermis. Lymphocytic infiltrate was seen in the entire dermis and mainly around the capillaries and appendages [Figure 2]. A diagnosis of LS was made on clinicopathological grounds and the patient was started on mid-potency topical steroids and emollients. No treatment was given for the nail dystrophy. Over a nine month follow-up period, hypopigmentation of skin lesions was noted, but nail lesions persisted.

Figure 1

Longitudinal ridging, splitting, and nail bed hyperkeratosis seen in the infant with nail lichen striatus.

Figure 2

Biopsy (hematoxylin and eosin staining -10X) showing mild hyperkeratosis with a few necrotic keratinocytes in the epidermis. Lymphocytic infiltrate is seen in the entire dermis, mainly around the blood vessels and appendages

DISCUSSION

LS, first identified as a distinct clinical entity by Senear and Caro in 1941, is an acquired, self-limiting linear dermatitis of unknown etiology but various genetic, infectious and environmental factors are thought to be involved.[4] LS presents as unilateral, asymptomatic, flesh-colored to red-brown flat topped papules. Although various hypotheses such as the course of blood vessels, lymphatics, peripheral nerves, Blaschko lines, and direction of body hairs were given for the linear distribution in LS, none could explain the various clinical morphology of the lesions.[5] Lesions are more commonly seen over the arms, legs, trunk, and less commonly over the face in decreasing order of frequency. Pruritus is rare and hypopigmentation is a frequent sequelae.[1]

Nail involvement is uncommon in LS. Some characteristics of nail involvement in LS have been shown in Table 2. Pathogenesis of nail changes in LS is mainly because of inflammation involving the nail matrix leading to abnormal keratin synthesis.[7] Nail changes may occur before,[8] simultaneously,[6] or after[7] the cutaneous eruption. Nail involvement in our case occurred after the skin eruption. Isolated nail LS without skin eruptions do occur and may have been underreported because LS is usually diagnosed based on skin eruptions.[6] Considering the history and clinical and histopathological examination, LS can be differentiated from linear lichen planus, linear psoriasis, linear epidermal nevus, linear verruca plana, linear porokeratosis, and other linear dermatitic eruptions.[8]

Table 2

Characteristics of nail lichen striatus

Histopathology of nail LS, although similar to skin LS, has a few differences. Compact orthokeratosis and hypergranulosis owing to interference with nail matrix keratinization is a feature of nail LS.[6] A nail matrix biopsy is required only when a nail matrix tumor is suspected.[6] Although LS is a self-limiting disorder, nail involvement in LS tends to go a prolonged course of six months to five years as opposed to six months to two years in isolated skin LS.[8]

No treatment is generally necessary due to its spontaneous resolution. This case has been reported due to the rarity of association between nail dystrophy and LS as well as the age of its occurrence - nine months being the youngest age of onset to be reported in the literature.