Dear Editor, Lichen striatus (LS) is a self-limiting linear dermatosis that predominantly affects children aged 5 months to 15 years and is distributed along the lines of Blaschko.[1] It is usually unilateral and single, although bilateral or multiple LS have been previously reported in the literature.[2] However, some cases of LS showing bizarre pattern of distribution along Blaschko lines have been documented in adults but not in children.[3] In this article, we present a child with linear and whorled LS lesions distributed along Blaschko’s lines involving right half of the body. A 4-year-old girl presented with asymptomatic streaks of scaly white patches on the right side of face, neck, chest, back, thighs, legs, and foot since birth. The lesions appeared first on the right thigh and later extended to involve the whole body on right side with in few months [Figure 1a-d]. She was born out of non-consanguineous marriage. Birth history was unremarkable. There was no history of any vesicular lesions, itching, personal or family history of atopy and no similar lesions in other family members. On examination, linear and whorled areas of scaly hypopigmented papules and plaques were present on the right side of the body along the Blaschko’s lines. Hair, nails, oral mucosa were uninvolved. Linear lichen planus, linear psoriasis, lichen striatus, incontinentia pigmenti, and linear and whorled nevoid hypomelanosis were the clinical differentials. On dermoscopy, whitish scar like areas with superficial scaling [Figure 2a] and accentuated surrounding network of pigmentation were present [Figure 2b].Figure 1: (a) 4-year-old girl with hypopigmented scaly lesions on right side of the face (b and c) right side of trunk and arms and (d) right lower limbFigure 2: (a) On videodermoscopy whitish scar like areas with superficial scaling seen, (b) Accentuated surrounding network of pigmentation present [120× magnification (Fotofinder)]Skin biopsy from a lesion on the right forearm showed mild hyperkeratosis, spongiosis, vacuolar alteration of basal layer and lymphocytic exocytosis with a mildtomoderate perivascular mononuclear inflammatory infiltrate and melanin incontinence in the dermis [Figure 3a and b]. It was diagnosed as a case of LS based upon the clinical and histopathological findings. Parents were reassured and emollients and tacrolimus 0.1% lotion for body lesions and tacrolimus 0.03% cream for face were prescribed for treatment.Figure 3: (a) Skin biopsy from a lesion on the right forearm showed mild hyperkeratosis, spongiosis with a mild to moderate perivascular mononuclear inflammatory infiltrate (hematoxylin and eosin staining; 10× magnification) and (b) vacuolar alteration of basal layer and melanin incontinence in the dermis (hematoxylin and eosin staining; 40× magnification)Linear dermatoses such as LS follow the lines of Blaschko, which are embryonic in origin. A somatic mutation in early embryogenesis results in the formation of an abnormal clone of cells, which on subsequent exposure to an environmental stimulus result in the formation of LS. Others believe that it is secondary to an autoimmune response mediated by T cells.[4] The pathogenesis of LS is poorly understood. However, various etiological factors most commonly implicated are atopy, drugs (adalimumab and etanercept), BCG and hepatitis B vaccination, minor trauma, insect bite, and viral infections such as varicella, influenza, and human herpes viruses 6 and 7. The histopathological findings are nonspecific and vary depending on the stage of evolution. Usually, a superficial perivascular lympho-histiocytic infiltrate is seen, which may extend focally into the lower part of epidermis causing vacuolar alteration of basal layer with melanin incontinence. The epidermal reaction pattern may include spongiosis, focal parakeratosis, and lymphocyte exocytosis.[1] The dermoscopic features of LS were gray granular pigmentation and white scar like lines. Gray granular pigmentation histologically corresponds to pigment-laden dermal melanophages of LS. In addition, a white scar-like line, only observed in LS, may also be helpful in differentiating from other conditions like inflammatory linear verrucous epidermal nevus (ILVEN). Although these dermoscopic features were not pathognomonic findings, these distinct features can be an important clue for differential diagnosis.[5] Nevoid conditions to be considered, which occur at birth or during infancy, are incontinentia pigmenti, linear and whorled nevoid hyper melanosis, hypomelanosis of ito, and epidermal nevi. Acquired conditions following Blaschko lines include psoriasis, porokeratosis, lupus erythematosus, pemphigus, scleroderma, fixed drug eruption, lichen planus, lichen nitidus, and lichen striatus.[6] Blaschko linear acquired inflammatory skin eruption (BLAISE) is characterized by inflammatory infiltrate and distribution along the lines of Blaschko. Blaschkitis more commonly occurs in adults, frequently involving the truncal areas, including the chest and abdomen. Histopathology changes show spongiotic dermatitis.[7] LS usually resolves spontaneously within 3–12 months, thus requiring symptomatic treatment only. The patient should be reassured and emollients and topical steroids may be used to relieve dryness and pruritus. For long-standing and rapidly progressing cases, once or twice daily application of tacrolimus ointment has shown efficacy.[8] Postinflammatory hypopigmentation or hyperpigmentation can develop as a sequela.[2] To the best of our knowledge, previously reported unusual patterns of LS are bilateral LS and multiple LS. LS rarely presents at birth. Our patient has an extensive unusual whorled and linear pattern of LS following Blaschko’s lines involving the complete right side of the body since birth. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.