Hello Mr Narasimhan and welcome to healthcare magic. I have read your query and it is heartening to see your concern for your wife. The problem you have described is a form of facial melanosis, the most common of which would be lichen planus pigmentosus,ashy dermatosis, melasma and photocontact dermatitis, which would fit your wife s present condition. I would need a few more details and a picture if possible to reach a final diagnosis & thereby help you out with the appropriate tretment. 1) Are there any other areas involved like the back, arm or other exposed sites? 2) Is the patch increasing in size ? 3) Any history of dye application which was then associated with more itching ? 4) What is the exact colour of the patch - blue black or brownish ? 5) Attach a photo if possible In all scenarios it is important for her to start with strict photoprotection. Advice her to avoid going out in the sun during the peak hours i.e 11AM to 4PM, and to carry an umbrella or cover herself with a dupatta whenever she moves out. The use of a broad spectrum sunscreen containing zinc oxide and benzophenones is a must and she should reapply this sunscreen every 3 hourly. Hope this was helpful. Awaiting your response.