摘要

Objectives: The objective of the study is to describe the clinical, histopathologic, and dermoscopy findings of exogenous ochronosis in 10 cases, and iatrogenic dyschromia in 6 cases. Differential diagnosis and treatment will also be discussed. Introduction: Facial dyschromias are common in skin of color and may result as complications of long term use of skin lightening products. The clinical manifestations have not been meticulously defined and consensus on proper treatment has not yet been established. Exogenous ochronosis is a paradoxical hyperpigmentation observed in patients who self-medicated with topical hydroquinone for the treatment of melasma. Iatrogenic dyschromia refers to alteration in skin color induced by medical treatment or pigment lasers. These conditions may look similar to other forms of dyschromia and dyspigmentation. Materials / method: Case series of exogenous ochronosis (18 cases) and iatrogenic dyschromia (6 cases) seen at the Research Institute for Tropical Medicine from March 2007 to December 2024. Results: Patients with ochronosis showed grayish black hyperpigmentation more prominent on the zygomatic areas. Dermoscopy revealed reddish brown clods and serpentine blood vessels. Iatrogenic dyschromia present with mottled brown and hypopigmented/depigmented patches. Histopathology of both conditions present with altered collagen and solar elastosis indicating moderate to severe dermal damage. Conclusion: The clinical , dermoscopic, and histological features of exogenous ochronosis and iatrogenic dyschromias show distinct features. Patients were advised to discontinue all skin lightening skin care products. Severe cases were advised laser resurfacing and collagen remodelling treatments. The treatments showed variable improvement in pigmentation.