This fungal infection can cause similar hypopigmented patches, but it is distinguished by a fine scale that is evident on stretching the skin (and a positive KOH test).
This is distinguished by a clear history of a preceding, more significant inflammatory dermatosis (like severe eczema) in that location.
Vitiligo is characterized by complete depigmentation (chalk-white patches) with sharp borders, whereas pityriasis alba is hypopigmented (an off-white color) with ill-defined borders.
This condition results in atrophic, porcelain-white plaques, which have a different texture and color than the simple hypopigmented patches of pityriasis alba.
