A young woman concerned about a pale area of skin on her back attended the surgery. The macule had recently been noticed by a new partner, although it was a difficult place for her to see so she thought it may have been there for much longer.
There were no other symptoms such as dryness or irritation and since it had first been pointed out a few weeks before, it had not appeared to increase in size. There was no past history of skin problems and she rarely exposed her back to the sun without appropriate sun creams.
Her grandmother had recently been diagnosed with a skin malignancy on her face, which had concerned her.
The area was well circumscribed, with no surface scale, and was smooth to the touch. The margin was irregular, but the adjacent skin looked normal. There were no other lesions when the patient's whole body was inspected and there were only a few benign naevi on the rest of her back.
The lesion is a naevus anaemicus. This is caused by localised vasoconstriction secondary to catecholamines in the skin.
Diascopy is useful when investigating this type of skin lesion and was consistent with the diagnosis. This involves pressing a glass slide onto the lesion, which then becomes indistinguishable from the surrounding tissue as the capillaries are emptied.
Dermoscopy also reveals the presence of melanin within the lesion, which distinguishes it from vitiligo, in which melanin is absent.
On checking her records, it appeared to have been present since birth, which is normal for this type of congenital lesion.
No treatment is required and she was reassured that there is no malignant potential. Patients troubled by such lesions can use skin camouflage creams to improve their appearance.
- Postinflammatory hypopigmentation
Dr Stollery is a GP in Kibworth, Leicestershire, and clinical assistant in dermatology at Leicester Royal Infirmary