Illness or Fever Hair Shedding
Reviewed by
Steven P., FAAD
Board-certified dermatologist
Updated on
Reviewed for accuracy
Table of Contents
What Is Fever Hair Shedding?
Fever hair shedding refers to the noticeable increase in hair loss that occurs after the body experiences a high fever or significant illness. This phenomenon is medically known as telogen effluvium, a temporary condition where hair follicles prematurely shift from the growth phase (anagen) to the resting and shedding phase (telogen). As a result, more hairs than usual are shed from the scalp, often leading to visible thinning.
The process is triggered by a shock to the system, such as a fever, infection, or acute illness. While the hair loss can be alarming, it is important to recognize that fever hair shedding is not permanent. In most cases, the underlying hair follicles remain healthy, and new hair growth resumes once the body recovers from the illness or fever. This type of hair shedding does not cause scarring or permanent damage to the scalp.
How Illness Causes Hair Loss
Illness can disrupt the normal hair growth cycle by introducing physical stressors that affect the body’s ability to maintain regular cellular functions. When the body is fighting an infection or recovering from a significant illness, resources are redirected toward essential processes, and non-essential activities like hair growth may be temporarily paused. This shift can cause a larger proportion of hair follicles to enter the telogen phase, resulting in increased shedding.
The link between illness and hair loss is most commonly observed in telogen effluvium. During this process, the shedding is diffuse, meaning it occurs across the entire scalp rather than in isolated patches. The hair loss is typically noticed two to four months after the illness, as the hair follicles complete their transition to the shedding phase. This delay can make it challenging to connect the hair loss directly to the illness, but understanding the timeline is key for accurate identification and management.
Why Fever Can Trigger Shedding
Fever is a common trigger for telogen effluvium because it represents a significant physiological stressor. When body temperature rises due to infection or inflammation, the stress can disrupt the normal functioning of hair follicles. The elevated temperature and associated inflammatory processes prompt many hair follicles to exit the growth phase prematurely and enter the resting phase.
This abrupt shift in the hair cycle is a protective response by the body, allowing it to conserve energy for fighting the underlying illness. However, it means that a large number of hairs will be shed simultaneously after a delay of several weeks to months. The extent of shedding often correlates with the severity and duration of the fever, but even moderate fevers can be sufficient to trigger this response in susceptible individuals.
Infections & Hair Loss
Infections, especially those accompanied by fever, are among the most common causes of temporary hair shedding. The body’s immune response to infection involves the release of inflammatory mediators, which can impact the hair follicles and disrupt their normal cycle. As the body prioritizes healing and immune defense, hair growth may be temporarily halted, resulting in more hairs entering the telogen phase.
Not all infections lead to hair loss, but those that cause systemic symptoms such as high fever, fatigue, or significant inflammation are more likely to trigger telogen effluvium. Viral infections like influenza and COVID-19, as well as bacterial infections, have been reported as triggers. The shedding is typically diffuse and does not cause scarring or permanent hair loss, with regrowth expected once the infection resolves and the hair cycle normalizes.
Different Illnesses That Can Cause Hair Shedding
A variety of illnesses can lead to increased hair shedding through the mechanism of telogen effluvium. Acute illnesses that cause high fever, such as influenza, COVID-19, and other viral or bacterial infections, are well-known triggers. In addition to infectious diseases, other physical stressors like surgery, major trauma, or rapid weight loss can also precipitate this type of hair loss.
Chronic illnesses, including endocrine disorders like thyroid disease, and conditions that lead to nutritional deficiencies, may also contribute to ongoing or recurrent episodes of hair shedding. The common factor among these conditions is the disruption of the normal hair growth cycle due to systemic stress or metabolic changes.
How Long Does Post Illness Shedding Last?
The duration of hair shedding after an illness or fever typically depends on the severity of the trigger and the individual’s overall health. In most cases of acute telogen effluvium, increased shedding begins two to four months after the illness and peaks over several weeks. The shedding then gradually decreases, with most people noticing improvement within six to nine months after the initial trigger.
Complete recovery is expected in the majority of cases, as the hair follicles remain intact and resume normal growth once the body has recovered. However, in rare situations, especially if the stressor persists or if there are underlying health issues, the shedding may last longer or become chronic.
Signs and Symptoms to Watch For
The most noticeable sign of fever or illness-related hair shedding is an increase in the number of hairs found on pillows, in the shower, or on hairbrushes. Shedding is typically diffuse, affecting the entire scalp rather than specific areas. The hair may feel thinner, and the ponytail may appear less full. In some cases, a fine fringe of new hair growth can be seen along the hairline as regrowth begins.
Unlike scarring forms of hair loss, telogen effluvium does not cause bald patches or significant changes to the scalp’s appearance. The hairline is usually preserved, and there is no redness, scaling, or discomfort. If hair loss is accompanied by other symptoms such as itching, pain, or patchy baldness, it is important to seek medical evaluation to rule out other conditions.
Can Stress of Illness Make It Worse?
Psychological stress, including the anxiety and worry that often accompany illness, can further contribute to hair shedding. Stress is a recognized trigger for telogen effluvium, and the combination of physical and emotional stressors may amplify the amount of hair lost. The body’s stress response can disrupt hormonal balance and immune function, both of which play roles in the hair growth cycle.
Managing stress during and after illness is important for overall recovery and may help reduce the severity or duration of hair shedding. Techniques such as mindfulness, relaxation exercises, and seeking support from friends or professionals can be beneficial.
Tips for Managing Fever Hair Shedding
While telogen effluvium is usually self-limiting, there are practical steps that can help manage hair shedding and support healthy regrowth. Gentle hair care is essential-avoid vigorous brushing, harsh treatments, and tight hairstyles that can further stress the hair. Use mild shampoos and conditioners, and minimize the use of heat styling tools.
Ensuring a balanced diet with adequate protein, vitamins, and minerals supports hair health. If nutritional deficiencies are suspected, consult a healthcare provider for appropriate testing and supplementation. Addressing any underlying medical conditions, such as thyroid disorders or iron deficiency, is also important. Patience is key, as hair regrowth takes time.
Frequently Asked Questions
What is telogen effluvium?
Telogen effluvium is a common cause of temporary hair loss that occurs when a significant number of hair follicles prematurely enter the resting and shedding phase. This shift is often triggered by physical or emotional stress, illness, fever, surgery, or other major changes in the body. The condition leads to diffuse hair shedding across the scalp but does not cause permanent baldness. Most people experience full regrowth once the underlying trigger is resolved. For a detailed overview, visit What Is Telogen Effluvium?.
Does every fever cause hair shedding?
Not every fever results in noticeable hair shedding. The likelihood depends on the severity and duration of the fever, individual susceptibility, and the presence of additional stressors. High fevers and significant illnesses are more likely to trigger telogen effluvium, but mild or short-lived fevers may not have the same effect. Other factors, such as nutritional status and overall health, also play a role.
Can hair grow back after illness-related loss?
Yes, hair typically regrows after illness-related shedding. Telogen effluvium is a reversible condition, and the hair follicles remain capable of producing new hair. Regrowth usually begins as the shedding tapers off, with visible improvement over several months. Complete recovery is expected in most cases, provided the underlying trigger has been addressed.
How soon after being sick does hair shedding start?
Hair shedding related to illness or fever generally starts two to four months after the triggering event. This delay occurs because hair follicles remain in the resting phase for several weeks before shedding. The timing can make it difficult to immediately connect the hair loss to the illness, but understanding this pattern is helpful for identifying telogen effluvium.
Is post-illness shedding permanent?
Post-illness hair shedding is almost always temporary. The hair follicles are not permanently damaged, and regrowth occurs once the body recovers and the hair cycle returns to normal. In rare cases, if the stressor persists or if there are underlying health issues, shedding may last longer or become chronic, but permanent baldness is not typical of telogen effluvium.
What treatments help fever hair shedding?
The most effective approach to managing fever hair shedding is to address the underlying cause and support overall health. Gentle hair care, a balanced diet, and correction of any nutritional deficiencies can aid recovery. Medical treatments are rarely needed, as telogen effluvium usually resolves on its own. If hair loss is severe or persistent, consult a healthcare provider for further evaluation.
Can COVID-19 or flu cause hair loss?
Yes, both COVID-19 and influenza have been reported as triggers for telogen effluvium. These infections can cause high fever and significant physical stress, leading to temporary hair shedding. The pattern and timeline of hair loss are similar to other causes of telogen effluvium, with regrowth expected once recovery is complete.
Fact Checked
Updated: December 30, 2025
Reviewed for accuracy against authoritative clinical sources and peer reviewed dermatology references. Educational content only.
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Reviewed by
Steven P., FAAD
Board-certified dermatologist
Updated on
Reviewed for accuracy
