Localised White Skin Lesions View GlobalSkinAtlas for Clinical Images
Approach to Diagnosis -
Any preceding redness- Consider post inflammatory hypopigmentation
Location - trunk with surface scaling - Pityriasis versicolor
No scale - Scar post chickenpox, Vitiligo , Progressive macular hypopigmentation
Localised large - nevus depigmentosus or nevus anaemicus
Localised genitals and flexures - Vitiligo
Face plus scale - Pityriasis alba mild atopic eczema
Sun exposed legs and arms - Idiopathic guttate hypomelanosis
Localised white skin lesions also signify a limited number of diseases. Working down, on the face consider pityriasis alba, a low grade form of eczema, poliosis, a white area on the forehead with a tuft of white hairs from birth. If poliosis appears as a new lesion consider localised vitiligo.
White spots on the chest or arms with fine surface scale is pityriasis versicolor. Rarely the flat warts of epidermodysplasia verruciformis can look like flat white macules but they have slight scale.
White spots on the chest with no surface scale could be progressive macular hypomelanosis or it could just be treated Pityriasis versicolor or macular vitiligo! You need to biopsy this one and ask for melanocyte stains. Pinta in the correct context is a rare infectious disease to consider with white macules on the chest.
White macules on the chest are sometimes seen in association with the greasy keratotic papules of Darier's disease. They may also be seen with associated skin cancers in patients with chronic arsenic exposure.
White spots on the forearms or lower legs are idiopathic guttate hypomelanosis, a type of inverse freckle from sun damage.
Porcelain white spots on the trunk with surface skin wrinkling is due to lichen sclerosus/ morphoea.
Porcelain isolated white spots without surface wrinkling could be malignant atrophic papulosis or Degos disease
Hypopigmentation on the trunk includes that on the chest, back and abdomen.
The commonest conditions causing hypopigmentation at these sites include vitiligo, Halo nevi, Pityriasis versicolor and post inflammatory either after liquid nitrogen or surgery to skin cancers. Post inflammatory hypopigmentation is also seen with discoid lupus erythematosus.
Localised morphea or lichen sclerosus can also present as hypopigmented patches but the underlying skin will be firm in morphea.
Undertreated psoriasis or eczema of the trunk may also present as hypopigmented patches but some evidence of these conditions elsewhere should allow you to make the diagnosis.
In the newborn look for the ashleaf macules of Tuberous sclerosus or pale connective tissue nevi. Segmental vitiligo may also be seen congenitally. Nevus depigmentosus and nevus anaemicus may also present as hypopigmented patches in this age group.
