What are two possible causes of sudden hair loss?
1. Alopecia areata: This is an autoimmune condition in which the body's immune system attacks the hair follicles, leading to hair loss. Alopecia areata can cause sudden hair loss in patches or complete hair loss (alopecia universalis).
2. Telogen effluvium: This is a temporary condition that occurs when a large number of hair follicles enter the resting (telogen) phase of the hair growth cycle all at once. Telogen effluvium can be caused by a variety of factors, such as stress, illness, childbirth, or certain medications.