Hypopigmented lesions are seen in
Melasma
Lichen planus pigmentosus
Urticaria pigmentosa
Pityriasis alba
In melasma brown / grey brown macular pigmentation with well defined scalloped margins. Pigmentation darkens on sun exposure.
Lichen planus produces hyper pigmented lesions.
Pityriasis Alba produces scaly hypo pigmented macules.