Idiopathic eruptive macular hyperpigmentation: Report of a case and review of the literature

Abstract

Idiopathic eruptive macular hyperpigmentation is a rare benign pigmentary disorder characterised by the sudden eruption of asymptomatic hyperpigmented macules involving the neck, trunk, and proximal extremities. Children and adolescents are usually affected. It is classified as a variant of acquired dermal macular hyperpigmentation. Herein, we report a case of idiopathic eruptive macular hyperpigmentation and review the existing literature. An otherwise healthy 9-month-old male infant presented with asymptomatic flat brown skin lesions which developed suddenly on his right leg. There was no history of preceding erythema, inflammatory lesions, viral exanthem, or drug exposure. Examination revealed multiple discrete, dark brown, round-to-oval macules over the right posterior leg. Based on clinical assessment, a diagnosis of idiopathic eruptive macular hyperpigmentation was made. The patient was managed conservatively with supportive skin cares and the lesions resolved spontaneously within several weeks without residual changes of pigmentation or scarring. The aetiology and pathogenesis of idiopathic eruptive macular hyperpigmentation remain unknown. The hyperpigmentation occurs sporadically in the absence of preceding illness, inflammation, or drug exposure. Endocrine factors and autoimmune phenomena have been hypothesized as potential triggers. Idiopathic eruptive macular hyperpigmentation may be underdiagnosed as it is often mistaken for disorders that are morphologically very similar including lichen planus pigmentosus, ashy dermatosis, fixed drug eruption, urticaria pigmentosa, and post-inflammatory hyperpigmentation. Active treatment is not necessary as it is a self-limiting disorder that typically regresses spontaneously within several months to years without sequelae. Idiopathic eruptive macular hyperpigmentation is a rare entity that should be considered in the differential diagnosis for children or adolescents presenting with hyperpigmentation disorders. Accurate and prompt recognition of this disorder is of great importance to avoid unnecessary investigations, expenses, and time-consuming therapeutic interventions.L6381499332022-06-08 <br />