Lichen striatus due to oral isotretinoin

Lichen striatus (LS) is an acquired asymptomatic linear inflammatory skin disease which was first described by Senar and Caro in 1941. It usually affects equally boys and girls during childhood and is only rarely seen in adults. The etiology of the disease is still not clear and remains obscure [1].
We would like to report a 23-year-old female patient who developed an LS lesion on her forearm while using oral isotretinoin for acne vulgaris.
A 23-year-old female patient noticed a mild pruritic rash, which had begun 3 months ago on the dorsum of her right hand and was slowly spreading in a linear fashion to her elbow in 3 months. When she presented to our department she also had nodulocystic acne and had been using oral isotretinoin (13-cis retinoic acid) 30 mg/kg/day for 7 months. There was no history of other systemic disease or medication use except oral isotretinoin. She also does not have a family history of a dermatological disease. The eruption formed erythematous, separated but linear-shaped papules (fig. 1). The patient was in good general health and her systemic physical examination was otherwise unremarkable. Her routine laboratory tests including complete blood count, glucose, liver enzymes, urea, creatinine, thyroid hormones, ferritin, vitamin B12 and hepatitis markers were normal. On histological examination by 4-mm punch biopsy material showed focal spongiosis with lymphocytic exocytosis, coarse collagen bundles in the papillary dermis and a histiocytic infiltrate seen around the vessels of the superficial plexuses (fig. 2). Clinical and histopathological features were consistent with LS. The patient did not receive any treatment regarding this condition and we decided to observe the lesion. The lesion resolved 1 month later without any treatment (fig. 3). She continued oral isotretinoin treatment for her acne in that period. At a 2-month follow-up visit her oral isotretinoin treatment was stopped too.
Lichen striatus is an uncommon, acquired, benign, self-limited skin disease and is characterized by a solitary, linear band of pink, red or skin-colored, flat-topped papules in a blaschkoid distribution [2]. Lichen striatus predominantly affects children of 5–15 years of age and is usually seen on the extremities as either a continuous or an interrupted band or bands [3]. In some cases it can also be seen on different locations such as the trunk or face. It is also reported with multiple and bilateral lesions in atypical...


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