It's mostly alopecia aereata, which is an auto immune disease, that causes sudden patch of hair loss. It's reversible and resolves spontaneously after around 6 months to 1 year. But before that, new patches might occur or the present patch might increase in size for which you need to get treated and prevent from increase in the size of lesion. Dandruff(seborrheic dermatitis) is separately another condition, which varies from mild to severe form and needs to treated to prevent diffuse hairfall.

Hello.Dandruff is the condition of scalp known as seborrheic Dermatitis. hair wash is the not permanent solution for Dandruff because Dandruff is fungal infection of scalp and occurs hairloss so you can visit Dermatologist nearby you. so he can assist your scalp and start treatment according to you

It's mostly Alopecia areata. Sometimes it's self limiting but if it's increasing in number or size then you need to take proper consultation. Consult any dermatologist.

Looks like alopecia areata.. don't worry it's treatable.. get a direct consultation with Dermatologist for treatment