It's not possible to comment based on this information and without a check up. It may or may not be Pityriasis alba. Please visit a pediatrician for a check up. It may be tinea versicolor, post inflammatory or other causes

Greetings Infant presenting with several small white spots on her arms and legs. While the presentation bears similarities to pityriasis alba, it could also resemble alternative dermatological conditions such as post-inflammatory hypopigmentation or tinea versicolor. Pityriasis alba itself often resolves on its own over several months, though using mild, fragrance-free moisturizers can help manage associated dryness

Visit physically to nearby pediatrician  or dermatologist.

Send me pictures

Send me pictures I will tell you because there are 100 types of skin infections are there where you will get white spots

Small pale patches on a baby's legs and hands are usually not pityriasis alba, which tends to show up on the face in slightly older children. At four months, this is more often mild dryness or early eczema leaving a lighter patch, or a harmless birthmark such as nevus depigmentosus. Most of these fade on their own with regular care.