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What Is Alopecia?

The word alopecia is derived from the Latin word for baldness.1 As an umbrella term, alopecia can apply to many types of hair loss.2 For example, the most common form of alopecia is androgenetic alopecia.1,3

Alopecia areata, however, differs from androgenetic alopecia and other types of alopecia, as it is an autoimmune disease. It occurs when a person’s immune system attacks their own hair follicles.1,2

 

What Is Alopecia Areata?

Alopecia areata is an autoimmune disease.1 Autoimmune diseases are conditions in which a person’s immune system attacks other tissues in their body. Researchers aren’t sure of the precise cause of autoimmune diseases, but some potential triggers may include bacteria, viruses, and medications. It’s also possible that a person’s genes can make them more likely to have an autoimmune disease.8

More than 80 types of autoimmune diseases exist and affect different organs and tissues,8 but alopecia areata affects hair follicles.1 These tiny structures sit just below the surface of the skin, producing different types of hair depending on their location on the body.9 Our bodies are covered in hair follicles, so alopecia areata can strike anywhere. It typically affects hair on the head and face.4

When hair begins to fall out, it sometimes does so in round, quarter-sized patches, though affected areas can be larger. For some people, this hair loss is a one-time event. For others, alopecia areata comes and goes and can last a lifetime. Each person may have a different experience with alopecia areata. Some people may regrow hair, while others do not.4 Hair regrowth can be spontaneous,10 or it can happen following treatment.11

There is no cure for alopecia areata, which affects an estimated 2% of the global population.4,12 And treatments were very limited until June 2022, when the United States Food and Drug Administration (FDA) approved a new medication for adults who have severe cases of alopecia areata.13 Fortunately, treatments can help regrow hair.11

Alopecia areata can be triggered by environmental factors like stress, injury, or illness. But in many cases, there is no clear answer as to why someone develops alopecia areata.1 However, researchers have begun to understand the science behind the disease. In addition to determining that alopecia areata is an autoimmune disease, researchers have identified a group of genes, the human leukocyte antigen (HLA) complex, associated with the condition. Variations to genes in the HLA complex may contribute to the disease. Additionally, alopecia areata appears to have some association with other autoimmune diseases, including vitiligo, lupus, and atopic dermatitis (a type of eczema).1,14

Alopecia areata may begin in childhood but can start at any age.2,15 In total, an estimated 6.7 million people in the United States and 160 million people globally have alopecia areata.16

This condition affects some populations disproportionately. For example, in the United States, Black people are more likely to have it than white people. Asian people, meanwhile, are less likely to have alopecia areata than white people.17

Patterns of Alopecia Areata

The distinct types of alopecia areata affect hair in different ways and affect people in different numbers.

  • Patchy alopecia areata is the most common type of alopecia areata. In this form of the disease, hair typically falls out in round patches about the size of a coin. Patchy alopecia areata often occurs on the scalp, leaving behind bare patches of skin. It can also appear on other parts of the body, such as the beard area.1,4

  • Unlike patchy alopecia areata, which involves losing separated quarter -sized patches of hair, often on the scalp,3 alopecia totalis causes a total scalp hair loss.18 The outlook for alopecia totalis tends to be comparatively poorer than patchy alopecia areata, with fewer people spontaneously experiencing hair regrowth.18

    An estimated .08% of the global population has alopecia totalis.19 It’s more common among children and young adults, but alopecia totalis can occur at any age. Like general alopecia areata, alopecia totalis also affects all genders in equal numbers.18

  • Alopecia universalis results in total body hair loss (not just the scalp, as in alopecia totalis).4,18 Alopecia universalis affects fewer than 200,000 people in the United States.20

The severity of alopecia areata may predict a person’s likelihood of the disease progressing to alopecia universalis. For example, one study found that people with more severe cases of alopecia areata were more likely to see their cases progress to alopecia totalis or alopecia universalis.12,21

 

Prevalence of Alopecia Areata

An estimated 6.7 million people in the United States and 160 million people worldwide have alopecia areata, which carries a lifetime risk of 2%.16 That estimated lifetime risk for children varies slightly, spanning from 1% to 2%.22

Alopecia areata is equally prevalent among all sexes and can occur at any age.2,15 One study estimated that the mean ages at time of alopecia areata diagnosis were 31 years for people assigned male at birth and 36 years for people assigned female at birth.23

Alopecia areata may run in families. Researchers estimate that between 0% and nearly 9% of adults who have alopecia areata also have a family member with the autoimmune disease. Evidence also indicates a possible association with certain other autoimmune diseases. People with alopecia areata face a 16% increased risk of these other autoimmune diseases, including autoimmune thyroid disease, vitiligo, and lupus erythematosus. In 39% of alopecia areata cases, the patient also has atopic dermatitis, a type of eczema.14,24

Causes and Risk Factors

What Causes Alopecia Areata
What Causes Alopecia Areata?

Classified as an autoimmune disease, alopecia areata is the product of a person’s immune system attacking their own hair follicles, causing hair to fall out. Researchers have made progress in understanding this disease, but work remains to be done. It appears that some genetic and environmental factors may contribute to alopecia areata.1,4

 

Alopecia Areata and Genetics

Genes appear to play a role in who gets alopecia areata.2,24 For example, one study found that among groups of identical twins with the disease, 42% to 55% of the time, both twins have it.25,26

Analysis of the human genome has shed some light on the genetic underpinnings of alopecia areata. We now know that the autoimmune disease may have an association with a specific gene in the human leukocyte antigen (HLA) complex.24 Playing a critical role in the body’s defense system, the HLA complex helps discern between proteins typically occurring in the body and proteins from foreign invaders. Researchers suspect that variations in the HLA complex may spur the immune system to attack hair follicles, leading to alopecia areata.1

Alopecia Areata Risk Factors

As an immuno-inflammatory disease, alopecia areata is sometimes associated with other autoimmune diseases. Some of the same genetic variations linked to alopecia areata are also linked to other autoimmune diseases. This means that there may be some overlap among genetic risk factors.1

For example, people with alopecia areata may face increased risk of:

  • A disease that affects the color of the skin, leaving patches or spots that are lighter in shade1,24,27. Read more about vitiligo.

  • A disease that causes inflammation throughout bodily tissues and organs1,28. Read more about lupus.

  • A condition in which allergens, such as mold or pollen, trigger asthma symptoms, including difficulty breathing, chest constriction, or cough1,29

  • A condition that causes chronic thyroid inflammation, limiting the gland’s ability to produce hormones over time1,30

  • A condition that causes the thyroid to become overactive1,31

Likewise, people with these diseases may also face an increased risk of alopecia areata.1

The triggers for the onset of alopecia areata remain unclear. It’s possible that illness, emotional stress, or injury can trigger the immune response that leads to the disease.1

In one study, certain factors were predictive of more severe disease. Those factors included changes to the nails (including ridges or pitting) and alopecia areata that continues for more than a year.32

 

Alopecia Areata Prevention

As an autoimmune disease with unclear causes, there are no known ways to prevent alopecia areata.33

Types of Alopecia

Patchy alopecia areata, alopecia totalis, and alopecia universalis are the predominant types of alopecia areata.4 Three types of alopecia that are not autoimmune diseases are:2

  • This type of alopecia is often called “male-pattern baldness” when it occurs in people assigned male at birth. People with this condition may experience hair loss dispersed over the entire scalp. However, androgenetic alopecia also occurs in those assigned female at birth, who may experience thinning hair over the entire scalp without a receding hairline.3

  • Traction alopecia stems from how people wear their hair. Certain styles, such as those that pull hair at the root, can cause hair to fall out over time. Typically, traction alopecia occurs in people assigned female at birth who are of African descent and who may wear their hair in tight braids.5

  • In frontal fibrosing alopecia, hair loss occurs slowly and scars the scalp around the forehead. It can also affect hair in different places on the body, including the eyelashes and eyebrows. The precise cause of frontal fibrosing alopecia has not been identified.6 It’s classified as a type of lichen planopilaris, another scarring type of scalp condition that can produce different hair-loss patterns. 7

Alopecia Areata Symptoms

Alopecia Areata Symptoms

An early symptom of alopecia areata is hair loss, which appears suddenly in round or oval patches on the scalp. Patches rarely show signs of scarring, rash, or redness. Sometimes hairs with wide tips and narrow bases, called exclamation point hairs, surround the patches. Patients occasionally report itching, tingling, or burning sensations at these sites before their hair falls out.4

In addition to hair changes, alopecia areata can also affect the nails, leading to ridges or pits. These symptoms are common in people who tend to lose more hair.4 The disease also may affect the beard, eyebrows, or eyelashes. Most often, it appears as patches on the scalp.1

After a scalp patch forms, alopecia areata progression can vary.4 Since this disease doesn’t destroy hair follicles,1 some people may regrow hair later.1,4 This hair regrowth may be white or gray and then return to a person’s natural hair color. Other people may develop additional patches while hair regrows in the original patch. Sometimes small patches of hair loss begin to connect, leading to bigger patches that can progress to alopecia totalis. In rare instances, a person loses all of their body hair to alopecia universalis.4

Most people with alopecia areata regrow hair but experience episodes of hair loss. People who experience more regrowth tend to have several common characteristics:4

  • Less extensive hair loss
  • Onset of the condition later in life
  • No changes to fingernails or toenails
  • No family history of the condition

Diagnosis and Treatment

Alopecia Areata Treatment

Often, when a person experiences alopecia areata symptoms, a dermatologist may check their hair and nails for signs of the disease and may use a dermascope (also called a dermatoscope), to closely study the scalp.34 A dermascope is a hand-held visual magnification device that healthcare professionals use to evaluate skin lesions.35 In some cases, doctors may order a blood test to learn more.34

Upon diagnosis, a dermatologist may wait to initiate treatment to see if hair may regrow on its own. If treatment is required, options will depend on several factors, which may include:36

  • Age
  • Extent of hair loss
  • Location of hair loss

Not everyone responds to treatment in the same ways, and the dermatologist may try multiple treatments to alleviate symptoms.36

Treatment options may include:34

  • Topical therapies (creams or ointments), which are applied directly to the skin
  • Injectable therapies
  • Systemic therapies (pills), which affect the immune system

Some of these medications may be prescribed off label, meaning that, although they are not approved by the FDA to treat alopecia areata, they have been approved to treat other conditions.36 Patients should discuss available treatment options and create a treatment plan with their doctor.11,16  

Because alopecia areata can be a distressing disease,1 self-care can be a critical part of living with alopecia areata. Some self-care options are cosmetic but may offer comfort. For example, some people with alopecia areata choose to wear wigs or hairpieces. Others may opt to shave their heads.11

People with alopecia areata may consider applying sunscreen to their scalps or keeping their heads covered to shield themselves from the sun’s damaging rays.11 For people who have lost their eyelashes or eyebrows, applying false eyelashes or stick-on eyebrows or wearing sunglasses may help protect the eyes.11

Because people with alopecia areata have a greater risk of developing other conditions, the National Institute of Arthritis and Musculoskeletal and Skin Diseases suggests that people with alopecia areata should continue to maintain their routine medical care. They may also want to consider seeking support for distressing emotions and experiences relating to alopecia areata.11

Global Impact of Alopecia Areata

Global Impact of Alopecia Areata

Alopecia areata affects about 160 million people worldwide.15 Researchers have estimated that the lifetime incidence of the autoimmune disease is 2%.37

To assess the burden of alopecia areata, researchers have used a measurement called global disability-adjusted life years (DALYs).38 According to the World Health Organization, DALYs are a measurement that accounts for time lost due to struggles with illness or disability as well as time lost due to premature death.39 In 2010, the number of global DALYs for alopecia areata was 1,332,800.37 Another study estimated that the global DALY rate per 100,000 people was 7.51 in 2019. The same study found that the DALY rate declined from 1990 to 2010, but the declines were modest.39

In a study that surveyed 176 people with alopecia areata in Iran, researchers determined that study participants with severe cases had higher rates of unemployment and more unstable courses of disease.40

A Canadian study of people with alopecia areata and their caregivers found that 95% “felt uncomfortable or self-conscious" about how they looked. More than half (57%) of pediatric patients and 65% of adult patients said that they avoided social gatherings and constantly worry about whether they’ll lose more hair or regrow hair.41

Frequently Asked Questions About Alopecia Areata

  • Genetics may play a role in alopecia areata. For example, if a person has a family member who has the autoimmune disease, that individual may face a higher risk of alopecia areata.4 One study with identical twins found that both twins had the condition in 42% to 55% of cases.25,26 However, in many cases, there is no family history of alopecia areata.4

    Evidence suggests that alopecia areata may be linked to genes in the human leukocyte antigen (HLA) complex, which plays an important role in managing the immune system.1 Variations within these genes may trigger the inflammatory attack on hair follicles that causes this condition.1

  • Yes, alopecia areata is an autoimmune disease.1 It happens when a person’s immune system attacks their own hair follicles, leading to hair loss.4

    There also appears to be an association between alopecia areata and other autoimmune diseases, such as vitiligo, lupus, and atopic dermatitis (a kind of eczem a).1,14 People with this condition also contend with an increased risk of developing these autoimmune diseases.24

  • No, alopecia areata is not contagious.33 Researchers have yet to determine the precise cause of the condition, but to date, they’ve established that it’s an autoimmune disease, possibly caused by environmental factors, and therefore not a contagious disease. It is possible that certain genes may make a person more likely to have it.1,8

  • Alopecia areata affects all genders in equal numbers. It occurs when something goes awry with the immune system, prompting the immune system to attack hair follicles. Hair falls out, but the hair follicle remains intact.1 Over time, people with alopecia areata may spontaneously regrow hair.3,42

  • Alopecia areata’s onset typically involves the sudden formation of round or oval-shaped patches of hair loss on the scalp. But the autoimmune disease may affect other body hair too, including the beard, eyebrows, or eyelashes. Hair loss typically is not accompanied by a rash, scarring, or redness, but some people report tingling, burning, or itching feelings in the areas right before they begin to lose hair.4

The information contained on this page is provided for your general information only. It is not intended as a substitute for seeking medical advice from a healthcare provider. Pfizer is not in the business of providing medical advice and does not engage in the practice of medicine. Pfizer under no circumstances recommends particular treatments for specific individuals and in all cases recommends consulting a physician or healthcare center before pursuing any course of treatment.

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