There are two main types of alopecia.

There is scarring alopecia non scarring alopecia.

Most of these are either hormonally triggered if they're non scarring or stress induced or medication induced and then scarring alopecia often are inflammatory or your own immune system triggering the alopecia.

Most patients experience increased shedding of hairs.

Some people will notice a widened heart and then patients that have acute hair loss can have redness itching or pain in the scalp sometimes tenderness.

Hair regrowth depends on the type of alopecia you have.

So a non scarring alopecia does grow back.

It does take time hair grows very very slowly.

It's like watching grass grow in your yard.

If you look out your window every day you don't see anything.

But if you look in a month you'll see thick lush grass and so the same thing applies with hair growth.

It's very slow and you're not going to see it on a day to day basis.

So in non scarring alopecia you can get full regrowth back to your normal baseline with scarring alopecia scar replaces those hairs.

And so really starting treatment early to prevent further loss is the best option because once those scars overtake a hair follicle the hair cannot grow back. 

Treatment options can span from watchful waiting for your immune system or for your level of stress to improve or you can go all the way to systemic oral treatments that suppress your immune system so it kind of depends on classifying that type of hair loss that you have but you may start with things like Rogaine or anti-inflammatory shampoos or topical steroids and work your way up to more aggressive oral treatments if need be.