You can find out about research intoall forms of Alopecia Areata in a wide range of journals; but the majority of research is published in medical, specifically Dermatological journals. For example:
International Journal of Dermatology
British Journal of Dermatology
When you go to the website of a journal there is often a search facility, so you can search the contents for relevant articles. You will usually get the titles of articles, often the abstracts, but more rarely the full article. You will see the “pdf” link at the bottom of the page. If you wish to obtain the full article there is often a cost element involved, but you may also obtain a copy by writing to the author.
Alternatively, you can find facilities which search the contents of a wider range of journals at, for instance, PubMed.