Could this be alopecia? I've been taking whey protein to try to restore health to my hair and nails (Photo)

A single bald spot can be many things from a fungal infection to alopecia areata. To be certain you need to see a doctor.

Yes it's quite likely it's alopecia areata, but be sure to see a physician to confirm. There are few conditions that have such a localized area of hair loss forming so quickly. See a dermatologist for treatment. Biotin and protein have no role in the treatment of alopecia areata. If it is confirmed to be alopecia areata, steroid injections are by far the best option for localized areas of hair loss. The patch may even regrow on its own. You'll want to sit down with a physician to understand the course and treatments available. Many individuals with patches of alopecia areata do really well with steroid injections.Here are the treatments with scientific evidence. steroid injections and topical steroidsMinoxidil (Rogaine)Diphencyprone and squaric acidAnthralinMethotrexate, sulfasalazine, prednisone, cyclosporinePlatelet rich plasmaAromatherapyOthers may be possible (list not complete)

This is a large bald area and certainly has a cause. You should see a dermatologist and get a diagnosis first and foremost.