Concise answer
Major physical or emotional stress can contribute to diffuse shedding, but stress should not be assumed to be the only explanation. The delay between a trigger and visible shedding can be several weeks.
Illness, surgery, rapid weight change, childbirth and severe emotional strain can shift more follicles into a resting phase.
Pattern hair loss, thyroid problems, nutritional factors, medicines and scalp disease may coexist, so timing and examination matter.
When evaluation may help
Seek professional review when shedding is persistent, patchy or associated with scalp symptoms, weight change, fatigue or a widening part.