Perdita di capelli: una panoramica delle diverse cause

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

La caduta dei capelli viene spesso descritta come un problema singolo, ma da una prospettiva clinica è più corretto considerarla un sintomo con molteplici cause sottostanti.

Diversi meccanismi biologici possono influenzare il ciclo di crescita dei capelli o il follicolo pilifero stesso, dando luogo a modelli, tempi e progressioni distinti.

Poiché questi meccanismi sono diversi, identificare il tipo di perdita di capelli a cui si può essere soggetti è un primo passo essenziale prima di considerare i passaggi successivi o il supporto.

The biological basis of hair loss

To correctly interpret hair loss, an understanding of the hair growth cycle and hair follicle structure is essential.

Each hair follicle contains a stem cell niche (the bulge region), which is critical for hair regeneration. In non-scarring alopecias, this structure remains intact, meaning that regrowth is, in principle, possible. In scarring forms of alopecia, however, chronic inflammatory processes destroy this stem cell region and replace it with fibrotic connective tissue, making regrowth impossible.

In addition, several biological mechanisms may contribute to hair loss:

  • Shortening of the anagen (growth) phase
  • Miniaturization of the hair follicle
  • Accelerated shift of follicles into the telogen (resting) phase
  • Immune-mediated inflammatory activity
  • Hormonal sensitivity to dihydrotestosterone (DHT)

Distinguishing between these mechanisms forms the foundation of the medical classification of hair loss.

Nella pratica clinica, la caduta dei capelli viene classificata in base al modo in cui viene colpito il follicolo pilifero e ai fattori che scatenano il cambiamento. Alcuni modelli sono reattivi e potenzialmente temporanei, mentre altri sono causati da sensibilità genetica o disregolazione immunitaria e possono avere un decorso a lungo termine.

Lo scopo di questa pagina non è fare diagnosi, ma aiutarti a riconoscere le categorie più comuni e a trovare la risorsa più adatta e approfondita.

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 pattern hair thinning in men and women. It is influenced by genetic predisposition and sensitivity to dihydrotestosterone (DHT).

Typical characteristics include:

→ Read the full medical overview of Alopecia Androgenetica

Not sure whether thinning reflects genetic pattern hair loss or temporary shedding? See our clinical comparison:
Alopecia Androgenetica vs Telogen Effluvium.

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

Wondering whether increased shedding is temporary or part of a pattern-based process? See our clinical comparison: Alopecia Androgenetica vs 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

When diagnosis matters

In clinical practice, different forms of hair loss frequently overlap. Diffuse shedding does not automatically indicate telogen effluvium, and gradual thinning does not always immediately confirm alopecia androgenetica. Accurate interpretation depends on understanding the underlying biological mechanisms rather than relying on a single visible symptom.

For situations where this distinction is essential, see our clinical comparison Alopecia Androgenetica vs Telogen Effluvium.

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.

La caduta dei capelli non sempre rientra perfettamente in una categoria, soprattutto nelle fasi iniziali. Alcune persone notano schemi di caduta sovrapposti o notano che la caduta rivela un diradamento sottostante già in fase di sviluppo.

Ecco perché la valutazione strutturata si concentra su modelli, tempi e fattori scatenanti, anziché su ipotesi basate solo sull'apparenza.

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.

For a structured comparison between the most common non-scarring hair loss conditions, see also: Alopecia Androgenetica vs Telogen Effluvium comparison.

Se non sei sicuro di quale categoria corrisponda meglio alla tua situazione, il TRIX Hair Check ti aiuta a chiarire il modello più probabile mediante domande basate su informazioni cliniche.

Inizia il controllo dei capelli (2 minuti)

Basato su oltre 20 anni di esperienza dermatologica

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.

What does the medical classification of hair loss mean?

The medical classification of hair loss refers to the dermatological framework that categorizes hair loss into non-scarring and scarring alopecias. This classification is based on follicular integrity, the presence of inflammation, and reversibility. Distinguishing between these categories is essential for determining prognosis, treatment strategy, and long-term expectations.

IMPORTANTE: questa pagina fornisce solo indicazioni generali. Per spiegazioni dettagliate, contesto diagnostico e indicazioni specifiche per ogni condizione, consultare le pagine dedicate linkate sopra.