摘要

Objectives: The objective of the research is to describe clinical cases of exogenous ochronosis and iatrogenic dyschromia, identify predisposing factors and assess the efficacy of treatments Introduction: Post-rejuvenation facial dyschromias in skin of colour may be a consequence of long term application of skin lightening drugs and cosmeceuticals or rejuvenation procedures such as chemical peels , pigment and resurfacing lasers. The clinical manifestations and predisposing factos have not been meticulously defined and consensus on proper treatment has not yet been established. Exogeneous ochronosis and iatrogenic dyschromias are examples of this skin condition. Materials / method: Once a diagnosis of exogenous ochronosis and iatrogenic dyschromia has been established either by dermoscopy or biopsy , patients were instructed to discontinue all previously applied topical drugs or cosmeceuticals. They were treated with skin barrier repair creams, topical antioxidants and sunscreens. Hyperpigmentation was treated with Q-switched or picosecond lasers to fragment dermal pigments. Er:YAG and 675 nm lasers were utilized to promote dermal remodelling and skin rejuvenation. The patients were followed up and improvements were documented by standardized photography Results: For exogenous ochronosis, male to female ratio is 1:9. All 10 patients used over the counter hydroquinone 2% solutions without sun protection for a mean duration of 5.3 years. Histopathology in all 10 cases showed a basket-woven stratum corneum in 20% of cases, epidermal atrophy in 10% and acanthosis in 20% of cases. Reddish brown deposits in various shapes and sizes were seen in the papillary dermis(100%) . Telangiectasia (40%), solar elastosis (50%) and perivascular infiltrate of lymphocytes (50%) were also noted. Melan A stain in 4/10 cases highlighted melanocytes with abnormal forms Conclusion: Management of exogeneous ochronosis and iatrogenic dyschromias usually require avoidance and discontinuation of all predisposing factors. The goal of treatment is to regenerate a healthy epidermis and encourage dermal remodelling. A carefully planned combination treatment with skin barrier enhancing cosmeceuticals, proper use of lasers, and skin boosters hold promise in treating these conditions