Types of hair loss: causes, patterns and medical differences

Rustig portret van een man en vrouw van middelbare leeftijd, zittend in natuurlijk daglicht met een neutrale, bedachtzame uitstraling.

Hair loss can occur for many biological reasons. Some forms are temporary and reversible, while others are progressive or involve permanent structural changes to the hair follicle. Understanding the different types of hair loss is essential for identifying patterns, determining possible causes, and knowing when medical evaluation may be necessary.

This overview explains the most common hair loss conditions, how they are medically classified, and how they differ in terms of mechanism and progression.

Identify your type of hair loss

Start the Hair Check (2 minutes)

Common patterns and causes of hair loss

Hair loss may present as gradual thinning (as seen in alopecia androgenetica), sudden shedding (common in telogen effluvium) or patchy bald spots (characteristic of alopecia areata).

The underlying causes can include hormonal sensitivity, immune system dysregulation, inflammatory processes, stress-related triggers, or genetic predisposition. Identifying the pattern of hair loss is often the first step toward accurate classification.

Medical classification of hair loss conditions

In clinical dermatology, hair loss disorders are classified into two principal categories based on follicular integrity:

Non-scarring alopecias (non-cicatricial)

Hair follicles remain structurally intact, meaning regrowth may be possible.

Examples include:

Scarring alopecias (cicatricial)

Inflammatory processes destroy the follicular stem cell region and replace functional follicles with fibrotic tissue, preventing regrowth.

An example includes:

Correct classification is essential, as treatment strategies and long-term expectations differ fundamentally between these groups.

Understanding whether a condition is scarring or non-scarring is the first step in determining prognosis, reversibility, and appropriate long-term management.

Non-Scarring Hair Loss Conditions

These conditions do not permanently destroy the hair follicle.

Klinische voorbeelden van alopecia androgenetica bij mannen en vrouwen, met terugwijkende haarlijn, verdunning op de kruin en diffuse, patroongebonden haarverdunning die kenmerkend is voor erfelijke haaruitval.

Alopecia androgenetica

Alopecia androgenetica is the most common cause of progressive hair thinning in men and women. It is influenced by genetic predisposition and sensitivity to dihydrotestosterone (DHT).

Typical characteristics include:

  • Gradual thinning at the temples or crown
  • Diffuse thinning along the central part line
  • Progressive miniaturization of hair follicles

→ Read the full medical overview of Alopecia Androgenetica

Voorbeelden van telogeen effluvium bij mannen en vrouwen, met diffuse haarverdunning over de gehele hoofdhuid zonder vast patroon, passend bij tijdelijk verhoogde haaruitval door verstoring van de haargroeicyclus.

Telogen effluvium

Telogen effluvium involves diffuse shedding triggered by physiological or psychological stress. It may occur after illness, surgery, childbirth, nutritional changes, or emotional stress.

Typical characteristics include:

  • Sudden increase in daily shedding
  • Even hair length among shed hairs
  • Often reversible once triggers resolve

→ Read the full medical overview of Telogen Effluvium

Voorbeelden van alopecia areata bij vrouwen, mannen en jongeren, met ronde, scherp begrensde kale plekken op de hoofdhuid, passend bij immuungemedieerde haaruitval met gelokaliseerde haarverliespatronen.

Alopecia areata

Alopecia areata is an immune-mediated condition in which the body targets hair follicles, leading to sudden patchy hair loss.

Typical characteristics include:

  • Round or oval bald patches
  • Possible spontaneous regrowth
  • Variable and unpredictable course

→ Read the full medical overview of Alopecia Areata

Scarring Hair Loss Conditions

These conditions involve permanent follicular destruction.

Klinische illustratie van frontale fibroserende alopecie (FFA) met terugwijkende haarlijn en lichte wenkbrauwverdunning

Frontotemporal fibrosing alopecia

Frontotemporal fibrosing alopecia is a chronic inflammatory scarring alopecia characterized by progressive recession of the frontal hairline. It most frequently affects postmenopausal women but can also occur in men and younger individuals.

Typical characteristics include:

  • Band-like frontal hairline recession
  • Eyebrow thinning
  • Smooth, pale scarred scalp skin
  • Permanent follicular fibrosis

Because FFA causes scarring, early medical evaluation is important.

→ Read the full medical overview of Frontotemporal Fibrosing Alopecia

Clinical comparison of common hair loss types

This table summarizes the key clinical differences between pattern hair loss, diffuse shedding, patchy hair loss, and scarring alopecia.

Alopecia androgenetica Telogen effluvium Alopecia areata Frontotemporal fibrosing alopecia (FFA)
Type Non-scarring (pattern hair loss) Non-scarring (reactive shedding) Non-scarring (autoimmune, patchy) Scarring (cicatricial)
Mechanism Follicle miniaturization driven by androgen sensitivity (incl. DHT) Temporary shift of many follicles into telogen (resting) phase Immune attack on follicles causing inflammation and patchy loss Chronic inflammation with fibrosis and permanent follicle destruction
Onset Gradual, often over years Often acute/subacute (weeks–months after a trigger) Sudden, with distinct patches Gradual but progressive, often subtle early signs
Pattern Temples/crown (men) or diffuse thinning with part widening (women) Diffuse, even shedding across the scalp Round/oval bald patches Band-like frontal hairline recession + often eyebrow thinning
Scalp findings Usually no inflammatory redness/scaling Usually normal; sometimes scalp sensitivity Often smooth patches; nail changes may occur Redness/scaling, burning/itch; loss of follicular openings in scarred areas
Reversibility Partially modifiable; typically long-term/progressive Often temporary; recovery possible once trigger resolves Regrowth often possible, course can fluctuate Not reversible in scarred areas
When to consider evaluation If progressive thinning or clear pattern changes develop If shedding persists > 6 months or triggers are unclear/ongoing If new patches appear, eyebrows are involved, or rapid spread occurs If hairline recession occurs with redness/scaling or eyebrow thinning

Note: This is general educational information and does not replace medical diagnosis. If symptoms progress rapidly or are unclear, medical evaluation is advised.

Male and female pattern hair loss

Pattern hair loss affects both men and women but may present differently. In men, thinning typically begins at the temples or crown. In women, diffuse thinning along the central part line is more common. These variations fall under androgenetic alopecia, the most prevalent type of hair loss worldwide.

When professional evaluation is recommended

While many forms of hair loss are benign or self-limiting, certain features warrant clinical assessment.

Seek medical evaluation if:

  • Hair loss is rapid or unusually severe
  • Bald patches develop suddenly
  • There is scalp pain, burning, or visible inflammation
  • Hair loss follows systemic illness or significant medication change
  • Shedding persists beyond 6 months without improvement
  • Hair loss is accompanied by systemic symptoms (fatigue, weight change, hormonal irregularities)

Early differentiation between non-scarring and scarring alopecia is important, as management strategies differ significantly.

A structured evaluation reduces the risk of misclassification and ensures appropriate next steps.

Why Proper Diagnosis Matters

Different types of hair loss can appear similar during early stages. However, treatment strategies vary significantly depending on whether the condition is:

  • Hormonal
  • Stress-induced
  • Autoimmune
  • Inflammatory and scarring

Clinical examination and dermatoscopy are often necessary for accurate classification.

Identify your type of hair loss

If you are unsure which category best matches your situation, the TRIX Hair Check helps you clarify the most likely pattern using clinically informed questions.

Start the Hair Check (2 minutes)

Based on 20+ years of dermatological expertise

Frequently Asked Questions about types of hair loss

What are the main types of hair loss?

Hair loss is medically classified into non-scarring and scarring forms. Non-scarring types include androgenetic alopecia, telogen effluvium, and alopecia areata. Scarring forms, such as frontotemporal fibrosing alopecia, involve permanent follicular destruction.

What is the difference between scarring and non-scarring alopecia?

In non-scarring alopecia, hair follicles remain intact and regrowth may be possible. In scarring alopecia, inflammation damages the follicle stem cell region and fibrosis replaces the follicle, preventing regrowth in affected areas.

What is the most common type of hair loss?

Androgenetic alopecia, also known as pattern hair loss, is the most common type of hair loss worldwide in both men and women.

Can hair loss be temporary?

Yes. Certain forms of hair loss, such as telogen effluvium, may be temporary and reversible once the triggering factor resolves. Scarring forms of hair loss are typically permanent.

What causes different types of hair loss?

Hair loss may be caused by genetic factors, hormonal sensitivity, immune system dysregulation, inflammatory processes, stress-related triggers, or medical conditions. The exact mechanism depends on the type of alopecia.

How can I identify which type of hair loss I have?

Gradual thinning may suggest androgenetic alopecia, sudden diffuse shedding may indicate telogen effluvium, and patchy bald spots may be associated with alopecia areata. Medical evaluation is often necessary for accurate classification.

When should I seek medical evaluation for hair loss?

Medical evaluation is recommended if you notice progressive hairline recession, sudden shedding, patchy bald spots, or persistent scalp redness and scaling.

This overview follows dermatological classification standards used in clinical practice to differentiate scarring and non-scarring forms of alopecia.

This page provides general educational information and does not replace medical diagnosis or treatment. For personalized medical advice, consult a qualified healthcare professional.