What is the duration between illness onset and the start of alopecia (hair loss)?

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Last updated: April 26, 2025View editorial policy

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From the Research

Hair loss typically begins 2-3 months after an illness or stressful event, with the most recent and highest quality study supporting this timeframe 1. This delayed reaction occurs because the illness disrupts the normal hair growth cycle, pushing more hairs into the telogen (resting) phase. When these hairs eventually shed, it creates noticeable thinning called telogen effluvium. The timing varies depending on the severity and duration of the illness, with COVID-19, high fevers, major surgeries, and severe infections being common triggers.

Some key points to consider:

  • Most people notice increased hair shedding when washing or brushing their hair.
  • The good news is that this type of hair loss is usually temporary, with regrowth beginning within 6-9 months as the hair follicles recover.
  • During recovery, maintaining good nutrition with adequate protein, iron, zinc, and vitamins, reducing stress, and gentle hair care can support regrowth.
  • If hair loss persists beyond 6-9 months or is accompanied by other symptoms like scalp pain or patchy loss, medical evaluation is recommended to rule out other causes.

It's also important to note that nutritional deficiencies, such as vitamin D, ferritin, and zinc deficiencies, can contribute to hair shedding, and supplementation may be beneficial in some cases 2, 3. However, biotin deficiency is not a significant factor in telogen effluvium, according to a recent study 4.

Overall, the key to managing telogen effluvium is to identify and address the underlying cause, maintain good nutrition and hair care, and seek medical evaluation if symptoms persist or worsen.

References

Research

Telogen Effluvium - a review of the science and current obstacles.

Journal of dermatological science, 2021

Research

Biotin Deficiency in Telogen Effluvium: Fact or Fiction?

The Journal of clinical and aesthetic dermatology, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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