alopecia

US /ˌæl.oʊˈpiː.ʃə/
UK /ˌæl.oʊˈpiː.ʃə/
"alopecia" picture
1.

the partial or complete absence of hair from areas of the body where it normally grows; baldness.

:
She was diagnosed with alopecia, which caused her hair to fall out in patches.
There are various types of alopecia, each with different causes and treatments.