Acquired Palmoplantar Keratoderma as a Rare Adverse Drug Reaction to Losartan: A Case Report

Palmoplantar keratoderma (PPK) is a heterogeneous group of disorders characterized by excessive epidermal thickening of the palms and Insert “and soles, and” may rarely arise as an adverse drug reaction. Drug-induced PPK has been most frequently linked to targeted kinase inhibitors; its association with angiotensin receptor blockers (ARBs) remains exceedingly rare and underrecognized. We report a 34-year-old woman with hypertension who developed progressive diffuse hyperkeratosis of the palms and soles approximately 2 months after initiation of losartan 50 mg once daily, with lesions present for approximately 2 months at the time of presentation. Hereditary, infectious, metabolic, and malignant etiologies were systematically excluded. Skin biopsy was declined by the patient’s family. Following discontinuation of losartan, appreciable clinical improvement was observed at 4 weeks, substantial improvement at 8 weeks, and complete resolution of palmoplantar hyperkeratosis at 12 weeks. Causality assessment using the Naranjo scale and World Health Organization–Uppsala Monitoring Centre (WHO-UMC) criteria supported a probable causal relationship. This is the second published case of losartan-induced PPK in the English literature and corroborates the probable role of angiotensin II type 1 (AT1) receptor blockade in acquired PPK. Clinicians prescribing ARBs should be aware of this rare but recognizable cutaneous complication.