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Brown skin colour is most often due to melanin, a protein produced in the epidermis by melanocytes. Various dermopathies have characteristic patterns of pigmentation.
For each of the twelve cases, study the image(s) and then answer the questions. You can click on the image to view a larger version if required.
Each case should take approximately 2 minutes to complete. There is a list of suggested further reading material at the end of the quiz.
Name this/these brown-coloured skin patch/es.
Phototoxic pigmentation
Describe the condition
Phototoxic reactions are especially prone to pigmentation even in fair skin. The sudden appearance of blisters and pigmented streaks on exposed areas in an asymmetrical distribution is characteristic of phytophotodermatitis, i.e., a phototoxic contact dermatitis to a plant containing psoralens. Irregular red and brown patches and dried-up blisters in this casewere due to fresh limejuice dripping onto the skin on a sunny day (berloque dermatitis).