Discovered brown patches on my body after vacation in sun which appear similar to melasma. What is this skin condition? (Photos)

Thank you for your question, Melasma needs a combination approach to get the best improvement and will need a series of treatments. In our practice, we combine Clear + Brilliant, peels, microneedling/PRP, Aerolase, and sometimes Erbium (Cool Laser) to get the best results. See an expert for a formal evaluation. Best, Dr. Emer

This is most likely not melasma as it is so acute in history. I would see a dermatologist who specializes in general dermatology issues, not cosmetics. Best, Dr. KaramanoukianLos Angeles

I agree that you must visit a medical dermatologist for evaluation.H Karamanoukian mD FACS

Thank you for the question. What you have is phytophotodermatitis a condition that happens when you come into contact with certain fruits or vegetables, such as limes, lemons, parsley, celery, and are in sunlight. A reaction occurs on the skin that results in these dark patches. Were you drinking margaritas or Corona with lime? The good news is phytophotodermatitis is not dangerous and the dark areas will resolve with time. If you would like to try to speed the resolution of the patches you could try hydroquinone. I hope this was helpful!

Now this is a great question as I now have to think back well over a decade ago since the Board exams. Given the streaky nature, I think it could be a UV induced phytophytodermatitis, the most common is lime. Light reacts with chemicals in certain fruits that contains psoralen like compounds, and can cause pigmentation. Perhaps a medical dermatologist can shed more information on this matter?Dr Davin Lim, Laser and aesthetic dermatologist. Brisbane. Australia. 

The first thing that comes to mind when I read "Mexico" and "sunbathing" and unusual brown patch patterns is splashes of lime.  If so, this would be a case of post inflammatory hyper pigmentation which could be treated using a combination of topical creams and specific light or laser therapy after a time period of sun avoidance.  However, if it is an infectious or inflammatory process, new areas may develop and further evaluation is needed.