Hyperpigmentation on back of lower leg

[frostygirl77]

I was in Florida on vacation for a few days. Our last day there, I noticed 3 small pink areas, about an inch long and half and inch wide, on the back of my right lower leg (mid-calf). About 10 days have passed, and now the areas are brown (hyperpigmented). One of them looks like it is getting bigger-the border of this area is dark and the middle is lighter. Almost like a healing bruise. The areas are smooth, and look like the melasma I have on my face. I also take Synthroid and am on birth control (not sure if this could be related to meds?) Any idea what this could be? Do I need to see a dermatologist? Thank you very much.

[frostygirl77]

Thank you for your time. I was recently diagnosed with Hashimoto's Disease and take 88mcg of Synthroid daily. And other than an elevated blood cortisol level in July, everything else is fine. Adrenal function was not tested when I had blood drawn two weeks ago. It looks like melasma, but the way it came about was weird-starting out pink and then turning brown. I made an appointment to see a dermatologist next week. Just to make sure it is nothing else.

[Dr Santos]

Hi,
How are you? What other symptoms are present? Hyperpigmentation is usually associated with history of skin inflammation, use of certain medications, endocrine diseases and even sun exposure. Some drugs  such as birth control pills react with melanin to form a drug-pigment complex and exposure to sunlight often stimulates sun-induced melanin synthesis. This is similar to melasma or chloasma spots which are appear most often as a result of hormonal changes.  If it persists, you may need to have this checked by your doctor for proper evaluation. Take care and do keep us posted. Warm regards.