Can Anesthesia Cause Hair Loss?

A variety of genetic and environmental factors are responsible for causing hair loss. The notion that general anesthesia almost always causes hair loss and hair fall is puzzling for a lot of patients.

Pressure-induced ischemia, stress, and hormonal imbalances during anesthesia affect the hair growth cycle and promote hair loss.

In this article, we’ll answer can anesthesia cause hair loss, whether you should worry and what can you do about your anesthesia hair loss.

How does anesthesia work?

General anesthesia is frequently given in surgeries to promote inhibitory and suppress excitatory neurotransmission. The neuro-depression mechanisms induce a state of unconsciousness and immobility that is essential for carrying out the surgery.

The anesthetic agents act on the neurotransmitters and postsynaptic channels to exert inhibitory and excitatory effects. Apart from suppressing neurotransmission, anesthesia also reduces the strength of the immune response.

The regular hair growth cycle

Before discussing the underlying mechanisms of anesthesia-associated, the readers need to acquire basic knowledge concerning the normal hair growth cycle. The three primary phases of the hair growth cycle are discussed below. 

Anagen Phase

Also known as the growing phase of the hair growth cycle, this phase is characterized by increased proliferation among the rapidly proliferating hair follicle cells. During this stage, the hair shaft is formed along with the deposition of a newer hair matrix.

As the cells in the hair follicle proliferate further, the hair shaft becomes longer and more mature. The duration of this phase and the length of the hair shaft is variable among different individuals. However, the average duration of the anagen phase is 2-6 years. 

Catagen Phase

Hair follicles enter the catagen phase as their growth is halted. This phase is a transition between the growing and shedding stages of the hair growth cycle.

During this phase, the hair bulb migrates upwards into the mid-dermis accompanied by cessation of mitosis of hair follicle cells and induction of apoptosis of these cells. The outer sheath of the hair bulb shrinks and becomes club-shaped, commonly known as a club hair. This phase lasts for only a few weeks. 

Telogen Phase 

The hair follicles remain in the telogen or resting phase for approximately 2-3 months. The formation of club hair is completed during this stage and remains in its place unless pushed outwards by newer anagen hair.

An average of 100 hair strands in this phase are shed each day. Hair follicles may enter the exogen phase involving active loss of hair. Shedding of hair during this phase is facilitated by manipulation during washing or brushing the hair.

What causes hair loss?

The frequency, severity, and pattern of hair loss may be determined by a single or multiple etiological factors, some of which are listed down below. 


Genetic variations and mutations play a key role in identifying the onset of hair loss. Genetics determines the structure of hormone receptors on hair follicles and the response of cells to these hormones. Androgenetic alopecia, commonly known as androgenetic alopecia has a significant genetic association. 

Alopecia Areata

Hair loss may also be a manifestation of the action of the immune system against the components of hair follicles called alopecia areata. As the immune system destroys hair follicles, hair loss occurs and bald patches on the scalp can be observed. 

Traumatic Alopecia 

This is characterized by the forceful shedding of hair enhanced by friction, traction during hairstyling, or physical trauma. 

Hormonal Imbalances

Endocrine disorders frequently disrupt, and slow the hair growth cycle and cause hair loss to varying degrees. Major hormones responsible for eliciting hair loss include estrogen, testosterone, cortisol, and thyroid hormones.

Medications and Therapeutic Procedures 

Administration of certain medications also results in hair loss, particularly the ones that are part of the cancer therapy regimens. Hair loss is one of the most prevalent adverse effects of radiotherapy and chemotherapy.

How does anesthesia cause hair loss?

A state of surgical stress is observed while administering anesthesia, which eventually leads to the release of hormones such as cortisol and catecholamines.

Cortisol disrupts the normal hair growth cycle and promotes the degradation of extracellular matrix components, ultimately resulting in hair loss. Similarly, the sympathetic nervous system also modulates the hair growth cycle by regulating the patterns of the proliferation of keratinocytes.

Hair loss after surgery also termed postoperative alopecia, is due to prolonged anesthesia and intubation, sometimes for more than 24 hours. As the head lies in the same position for long hours, increased pressure disrupts the blood flow toward the scalp, resulting in hair loss.

Post-operative stress, anxiety, and other psychological conditions also predispose an individual to develop post-operative hair loss. Studies suggest that repositioning of the head, both intraoperatively and postoperatively as well as psychological counseling assists in combating associated hair loss.

Telogen Effluvium

Telogen effluvium is a common type of hair loss pattern observed in individuals who received general anesthesia. It is a self-limiting, diffuse, and non-scarring form of hair loss affecting hair follicles in the telogen phase of the hair growth cycle.

Surgical stress is one of the many triggering factors that promote hair loss. During the onset of telogen effluvium, an individual experiences hair loss that exceeds the normal daily limit of 100 telogen hair strands per day. The condition is self-limiting and the symptoms regress upon the removal of the triggering factors.

How to treat hair loss after anesthesia?

Anesthesia-associated hair loss is self-limiting and subsides a few months after surgery as normal hormone levels are restored and stress is reduced. To accelerate hair growth and gain back the original volume, here is what an individual can do. 

Alleviate Stress 

Psychological counseling after surgery can greatly reduce the severity of hair loss. Hormones including cortisol are released when an individual is under stress, and disrupt the hair growth cycle, eliciting hair loss.

Postoperative counseling of the patient assists in maintaining normal levels of stress hormones and maintaining a normal hair growth cycle.

Healthy Diet

Consuming a well-balanced nutritious diet can help an individual in restoring the levels of important nutrients, vitamins, and minerals in the body. These also influence hormonal balance and maintain normal growth of hair both directly and indirectly.


Pharmacologic formulations can be used when a person desires to speed up hair regrowth. Topical treatment with minoxidil, also called Rogaine, is an effective way of restoring hair growth.

Minoxidil improves blood flow toward hair follicles and increases the duration of the anagen or growing phase of the hair growth cycle. 

Another popular approved medication is finasteride.


In some cases, people are less likely to grow their hair back and the medications may fail to produce any therapeutic effects. In such cases, micro-pigmentation plays a significant role in boosting confidence in individuals suffering from post-operative hair loss. The process involves creating an illusion of hair follicles using pigments of different hues.

Hair Transplant

Recently, hair transplant surgery has become a popular hair restoration method for people looking for a way to solve their female and male pattern baldness.

There are two hair transplantation procedures you can choose from namely FUE (follicular unit extraction) and FUT (follicular unit transplantation).

Hair Products

For those who can’t cope with the surgical procedure, any form of plastic surgery or hair restoration surgery is out of the question.

While some turn to minoxidil and finasteride, their side effects are also a concern for victims of hair thinning and hair shedding.


Hair loss is an inevitable adverse effect of general anesthesia during surgery. It disrupts blood flow toward the follicles and affects the replication of hair follicle cells. Surgical stress induces a state of stress-associated hair loss, usually regarded as telogen effluvium.

Despite being unpreventable in the majority of cases, individuals can consume a healthy diet, modulate stress, and treat any chronic conditions to counter the severity and duration of hair loss. There are also micro-pigmentation, cosmetic surgery, and hair products to help combat sudden hair loss.


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Dr. Ahmad Chaudhry M.B.B.S.
Dr. Ahmad Fayyaz Chaudhry earned his MBBS degree from Punjab Medical College, Faisalabad, in 2020. During graduation, he enrolled himself in the Dermatology Ward DHQ Hospital Faisalabad for all the necessary training required to pass the bachelor's exam and encounter dermatological diseases daily. Currently, he is posted as a House Physician in the Medical Unit 3 Allied Hospital Faisalabad, where he encounters all kinds of hepatic, cardiac, neurological, and dermatological diseases daily.

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