Environmental triggers including changing day length and temperature shifts can push a larger proportion of follicles into the resting phase simultaneously, leading to increased shedding a few months later. Autumn and early spring are the most commonly reported periods of increased shedding.
Seasonal shedding is self-limiting and typically resolves over two to three months. Shedding that is markedly higher, accompanied by visible thinning, or present year-round warrants investigation for thyroid function, iron deficiency, or scalp conditions.