Hair loss caused by cancer treatments that affect rapidly dividing hair follicle cells.
Chemotherapy-induced hair loss is often anagen effluvium, meaning hairs are affected during the active growth phase. It can cause rapid shedding from the scalp and sometimes eyebrows, eyelashes and body hair. The extent depends on the drug, dose and schedule. In many cases hair regrows after treatment, but texture, colour or density may temporarily change. Some regimens can rarely cause persistent thinning, so oncology and dermatology input is appropriate when regrowth is delayed.
NHS hair loss: https://www.nhs.uk/symptoms/hair-loss/ ; DermNet hair loss: https://dermnetnz.org/topics/hair-loss
