A short, 2-3 week transition phase of the hair cycle between active growth (anagen) and rest (telogen). The follicle shrinks and detaches from its blood supply. Only about 1% of hairs are in catagen at any moment.
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Not medical advice. General education only; it does not replace diagnosis or treatment by a licensed professional. Consult a board-certified dermatologist before starting, stopping or changing any treatment.
⚠️ When to see a doctor — don’t self-treat
- Sudden patchy or circular bald spots
- Redness, scaling, pus, pain or itch (possible scarring alopecia — treat urgently)
- Broken hairs or rapid loss
- Loss with body-wide signs (weight loss, fatigue, cycle changes, acne, extra hair)
- Loss right after a new medication
- Any hair loss in a child