Pustular Eruption in a Patient Treated With Trametinib

A 14-year-old girl developed skin lesions after starting trametinib for a hypothalamic-chiasmatic pilomyxoid astrocytoma. Examination revealed pustules and erythema, diagnosed as Malassezia folliculitis and seborrheic dermatitis. Trametinib was discontinued, and treatment with oral itraconazole and topical creams led to improvement. Malassezia folliculitis is often misdiagnosed as acne, but dermoscopy can aid in its identification. While trametinib can cause various dermatologic toxicities, including acneiform dermatitis, most can be managed without stopping the drug. Dermatologists should recognize these reactions to avoid unnecessary treatment interruptions.