A 13-year-old boy with a personal history of Asperger's syndrome, attention deficit hyperactivity disorder and hypothyroidism, on treatment with methylphenidate, risperidone and levothyroxine. He was referred to the dermatology department for a lesion on the right lower limb, which had been growing progressively for a year. It was asymptomatic, with no clinical signs such as pain or pruritus. She had not received any treatment, nor did she report any triggering factor. Examination revealed a plaque, indurated on palpation, with a central dyschromic area and a purplish halo, with a linear distribution in the mid-distal third of the right outer thigh. There were no other skin lesions or accompanying systemic symptoms.

Laboratory tests were requested, including a complete blood count, biochemistry, antinuclear antibodies (ANA) and serology, urine test and biopsy of the lesion. The results were normal, with negative ANA, anti-Sm, anti-RNP, anti-SSA, anti-SSB, anti-Jo1 and anti-Scl70. Serology for Borrelia burgdorferi was negative and urinalysis showed no abnormalities. Histopathology was compatible with the diagnosis of morphea.
Given a linear morphea in infancy without joint involvement or aesthetic deformity, it was decided to initiate topical corticosteroid treatment with fluticasone propionate, one application per day for 2 months, followed by topical calcipotriol, also one application per day. After almost a year of follow-up, the lesions have stabilised.