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What is A 17 year old girl with acne has been taking a drug for the last two years.She now presents with blue black pigmentation of nails.The likely medication causing above pigmentation is- and explain in detail?
Mincycline induced pigmentation in acne- due to accumulation of iron in dermal macrophages occur with prolonged therapy 1-3 years high dose 200-300mg/day three different patterns - Localised at sites of previous inflammation -acne scars pretibial area generalised over the sun exposed sites and nails Ref Harrison 20th edition pg 1213