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 . 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 . we herein report the case of a 9-month - old infant with ls and onychodystrophy . 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 . over a nine month follow - up period , hypopigmentation of skin lesions was noted , but nail lesions persisted . longitudinal ridging , splitting , and nail bed hyperkeratosis seen in the infant with nail lichen striatus . 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 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 . 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 . lesions are more commonly seen over the arms , legs , trunk , and less commonly over the face in decreasing order of frequency . pathogenesis of nail changes in ls is mainly because of inflammation involving the nail matrix leading to abnormal keratin synthesis . isolated nail ls without skin eruptions do occur and may have been underreported because ls is usually diagnosed based on skin eruptions . 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 . 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 . 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 . 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 .
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 .