Common Hair Loss Types: A Side-by-Side Reference

How to read this reference table

Alopecia is the medical term for hair loss. Dermatology sources divide it into two broad categories: non-scarring alopecia and scarring alopecia, also called cicatricial alopecia. In non-scarring forms the hair follicle is preserved, so regrowth is at least possible. In scarring forms the follicle is permanently destroyed, which is why early recognition matters so much.

The table at the end of the page compares the most frequently discussed types on six attributes: type, category, typical pattern, onset and course, reversibility, and who is most often affected. Read each row as a description to compare against your own experience, not as a diagnosis. Many people find that one row fits better than the others, and some find that two or three rows overlap.

• Non-scarring does not automatically mean temporary, and scarring does not automatically mean the process is over.
• The same word, alopecia, describes a category of conditions, not one single disease.
• Pattern is one clue among several; a clinician also looks at scalp symptoms, hair pull findings, trichoscopy, and sometimes a biopsy.
• Prevalence figures are included only where a U.S. population source supports them.

Sources: Nature Reviews Disease Primers (PMC/NLM), Life (MDPI) via PMC/NLM, Cureus (PMC/NLM)

Androgenetic (pattern) hair loss

Androgenetic alopecia is the most common type of hair loss. It is genetically determined, polygenic, and androgen-dependent, and it affects approximately 50% of men by age 50. In men the classic pattern is a receding hairline with diffuse loss at the crown. In women the pattern is usually diffuse thinning with preservation of the frontal hairline.

Standard grading systems give these patterns a shared vocabulary: the Hamilton-Norwood scale for men and the Ludwig system for women. In the Hamilton classification, Types I through III describe scalps that are not bald, while Types IV through VIII describe scalps described as bald, with later types showing confluence of frontal and crown loss into a horseshoe-shaped pattern.

Pattern hair loss is chronic. Hair loss tends to recur when treatment is discontinued, so the goal of most treatment plans is maintenance rather than a permanent cure.

• Category: non-scarring.
• Typical pattern: men, receding hairline and crown thinning; women, diffuse thinning with frontal hairline sparing.
• Course: gradual and progressive; genetically determined and androgen-dependent.
• Grading: Hamilton-Norwood for men, Ludwig for women.
• Reversibility: chronic; recurs if treatment stops.
• Who is most often affected: about 50% of men by age 50; also common in women after menopause.

Sources: Nature Reviews Disease Primers (PMC/NLM), Journal of Cutaneous and Aesthetic Surgery (PMC/NLM), American Family Physician (American Academy of Family Physicians), Cureus (PMC/NLM)

Telogen effluvium

Telogen effluvium is excessive shedding of hair that has been pushed out of the growth phase. It appears either as an acute, self-limiting form triggered by events such as childbirth, febrile illness, major surgery, or rapid weight loss, or as a chronic form that is often associated with female pattern hair loss. People commonly describe clumps of hair in the shower or on the brush.

Shedding usually begins about three months after the trigger and tends to stop once the precipitating cause is removed. Acute telogen effluvium is generally considered to last under six months; chronic forms last longer. No verified U.S. prevalence estimate for telogen effluvium was supplied in the literature reviewed here, so this page does not state one.

• Typical pattern: diffuse shedding across the scalp rather than bald patches.
• Onset and course: abrupt onset, usually three to six months after a trigger; often self-limited.
• Reversibility: hair typically regrows after the cause is removed.
• Common triggers: childbirth, febrile illness, major surgery, rapid weight loss, stress, medication, and hormonal changes.
• Who is most often affected: women around childbirth are a classic group, but it can follow any of the listed triggers in either sex.

Sources: Nature Reviews Disease Primers (PMC/NLM), Life (MDPI) via PMC/NLM, American Family Physician (American Academy of Family Physicians)

Alopecia areata

Alopecia areata is an autoimmune disorder characterized by transient, non-scarring hair loss with preservation of the hair follicle. It affects nearly 2% of people at some point in their lifetime. In a U.S. employer-sponsored insurance population from 2016 to 2019, prevalence was 0.199% to 0.222% and incidence was 91.46 to 92.90 cases per 100,000 patient-years. Roughly 5% to 10% of prevalent and incident cases were alopecia totalis or alopecia universalis.

The three main types are patchy alopecia areata, the most common form, with one or more coin-sized patches; alopecia totalis, with complete or near-complete scalp hair loss; and alopecia universalis, with complete or near-complete loss of scalp, face, and body hair. Other recognized patterns include diffuse alopecia areata, which causes sudden thinning all over the scalp, and ophiasis, a band-like loss along the sides and back of the head.

Alopecia areata can begin at any age but first appears by age 40 in more than 80% of patients and by age 20 in 40%. Most patients recover within the first year, although an estimated 4.5% to 36.1% may ultimately progress to alopecia totalis or universalis. The scalp is the most common site of involvement.

• Category: non-scarring autoimmune.
• Typical pattern: sudden round or oval patches; may progress to totalis or universalis.
• Onset and course: sudden, most often in teens, twenties, or thirties; unpredictable, with possible regrowth and recurrence.
• Reversibility: hair often regrows within a few months; there is no cure, and regrowth is less likely in extensive forms.
• U.S. prevalence: 0.199% to 0.222% in the 2016 to 2019 cohort studied.
• Who is most often affected: both sexes and all age groups, with first onset by age 40 in more than 80% of patients.

Sources: National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), U.S. National Institutes of Health, Nature Reviews Disease Primers (PMC/NLM), JAMA Dermatology (PMC/NLM), Clinical, Cosmetic and Investigational Dermatology (PMC/NLM), National Alopecia Areata Foundation

Traction alopecia

Traction alopecia results from chronic mechanical pull on the hair, often from hairstyles that are tight enough to tug at the roots, such as braids, buns, or extensions. It frequently starts around the hairline. One peer-reviewed review describes it as reversible in the early stages but potentially irreversible once sustained traction has led to follicular deletion.

That description is an important qualification rather than a universal rule. Because the evidence for reversibility comes from a single review, the safest reading is that early change is more likely to recover than long-standing change. No verified U.S. prevalence estimate for traction alopecia was supplied in the literature reviewed here, so this page does not provide one.

• Typical pattern: loss from chronic mechanical traction, often starting around the hairline.
• Typical cause: hairstyles that pull on the hair.
• Reversibility: described as reversible in the early stages, with risk of irreversible loss from sustained traction.
• Who is most often affected: people who regularly wear tight braids, buns, or extensions; the pattern is described in the dermatology literature without a single demographic group.

Sources: Nature Reviews Disease Primers (PMC/NLM)

Scarring (cicatricial) alopecias

Scarring alopecias involve permanent destruction of the hair follicle and loss of the follicular ostium, the small opening through which a hair emerges. They are rarer than the non-scarring forms. Named conditions in this group include lichen planopilaris, frontal fibrosing alopecia, chronic cutaneous lupus erythematosus, folliculitis decalvans, and central centrifugal cicatricial alopecia.

Lichen planopilaris is a chronic inflammatory disease that causes permanent follicle destruction, usually with patchy scalp loss and follicular erythema at the margins of bald patches. Frontal fibrosing alopecia is a variant of lichen planopilaris with a different pattern, affecting the frontal and frontotemporal hairline and the eyebrows, and it most often affects postmenopausal women. Central centrifugal cicatricial alopecia is most common in women of African descent.

Because the follicle is destroyed, early intervention is important to prevent further permanent loss. No verified U.S. prevalence estimates were supplied for the individual scarring alopecias, so this page does not give specific rates for them.

• Category: scarring, also called cicatricial.
• Typical pattern: permanent follicle destruction with loss of follicular ostia.
• Named conditions: lichen planopilaris, frontal fibrosing alopecia, chronic cutaneous lupus erythematosus, folliculitis decalvans, and central centrifugal cicatricial alopecia.
• Who is affected: frontal fibrosing alopecia in postmenopausal women; central centrifugal cicatricial alopecia in women of African descent.

Sources: Nature Reviews Disease Primers (PMC/NLM), Life (MDPI) via PMC/NLM, Cureus (PMC/NLM), NYU Langone Health

Other less common patterns

Two additional patterns are worth knowing because they can be mistaken for one of the categories above. Trichotillomania is a hair-pulling impulse-control disorder that produces irregular patches or a tonsural pattern of loss, with broken hairs firmly attached to the scalp. Tinea capitis is a curable fungal infection that presents in children with patchy hair loss and signs of scalp inflammation such as redness and scaling.

These examples show why location alone is not enough. A patch of lost hair near the hairline could reflect traction, a scarring process, or another cause, and the surrounding scalp often provides the distinguishing clues.

• Trichotillomania: irregular patches, often with broken hairs still attached.
• Tinea capitis: patchy loss with scalp inflammation; most often in children and treatable.
• Either can resemble a non-scarring alopecia at first glance.

Sources: Nature Reviews Disease Primers (PMC/NLM), Life (MDPI) via PMC/NLM

What this table can and cannot tell you

The comparison above can help you put a name to a pattern and understand whether a description is considered non-scarring or scarring, common or rare, temporary or persistent. That is genuinely useful for asking better questions and for recognizing which educational page to read next.

It cannot substitute for an examination. Several types share overlapping features, and a clinician may use a hair pull test, dermoscopy, or a scalp biopsy to separate them. Nothing here establishes a diagnosis or recommends a treatment plan for any individual.

Prevalence figures are included only where a U.S. population source supports them. For androgenetic alopecia the widely repeated figure of more than 50 million men and 30 million women comes from an academic medical center patient-education page and is not corroborated by the peer-reviewed sources used here, so it is best treated as an estimate rather than a verified count. Telogen effluvium, traction alopecia, and the individual scarring alopecias are described without specific U.S. rates because those numbers were not available in the reviewed literature.

• The table describes patterns, not people, and it does not diagnose.
• Some types look alike until a clinician examines the scalp more closely.
• Where a rate is not given, that reflects the limits of the published U.S. data reviewed, not an absence of the condition.
• Clinical judgment is required to distinguish overlapping patterns.

Sources: Nature Reviews Disease Primers (PMC/NLM), NYU Langone Health, Journal of Cutaneous and Aesthetic Surgery (PMC/NLM), Cureus (PMC/NLM)

Hair-loss types side by side

The table below brings the same attributes together for the hair-loss types covered on this page. It is intended as a quick visual companion to the explanatory sections above. Read across a row for a single type, or down a column to compare types on the same attribute.

• Read across a row for a single type; read down a column to compare types on the same attribute.
• A row fitting your experience is a starting point for discussion, not a conclusion.

Sources: Journal of Cutaneous and Aesthetic Surgery (PMC/NLM), Nature Reviews Disease Primers (PMC/NLM), Cureus (PMC/NLM), American Family Physician (American Academy of Family Physicians), Life (MDPI) via PMC/NLM, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), U.S. National Institutes of Health, JAMA Dermatology (PMC/NLM), National Alopecia Areata Foundation, NYU Langone Health