White circle on back that does not tan

My daughter has a white spot on her back; a perfect circle, that will not tan. As it is summer, she has gotten some sun and this spot will not color.

[Bhupinder Kaur, MD]

Hello,
You have not mentioned the age of your daughter, however for such white spots the possibilities are of pityriasis alba and pityriasis versicolor. Pityriasis alba is a flaky, hypopigmented, patchy dermatitis with fine scales involving the face and, at times, the neck and shoulders. No treatment is required and the patches in time will settle in due course of time. The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used. Severe cases may require PUVA therapy. Pityriasis versicolor is caused due to a fungal skin infection.

You can discuss these treatment options with your dermatologist.
I hope it helps. Take care and regards.