Hypopigmentation is a skin colour that is paler than normal for that person or that site on the body. It is due to reduced pigment. Hypopigmentation can be generalised or localised. Around 1 in 20 people have at least one hypopigmented macule.
Localised hypopigmentation may appear as single or multiple paler/white patches.
Possible diagnoses to consider in this instance are thermal burn, vitiligo, pityriasis alba, pityriasis versicolour, halo naevus. (And also, idiopathic guttate hypomelanosis, progressive macular hypomelanosis, lichen sclerosis and leprosy.)
Generalised hypopigmentation is associated with reduction in melanin pigmentation at birth which may be racial or due to albinism.
Inflammatory and infective causes of hypopigmentation are usually self-resolving with time, often weeks up to months. Currently there is no treatment for achromia due to scarring. See our vitiligo page for associated treatment options.