Alopecia refers to hair loss resulting from disease, dysfunction, or hereditary predisposition. There are various types of alopecia affecting both men and women, with some being more common and others quite rare. Approximately 97% of alopecia cases are non-scarring and reversible, meaning they do not involve damage to the hair follicle stem cells. The remaining 3% typically involve scarring alopecia, where significant damage to the hair follicles occurs, making these forms irreversible.
Alopecia and Its Types
- Androgenetic Alopecia
Androgenetic Alopecia (AGA) is by far the most common cause of hair loss in both men and women. The term “androgenetic” accurately reflects the dual origin of the condition—“andro-“ refers to the hormonal component, and “-genetic” to the hereditary factor involved in its pathogenesis.
Androgenetic Alopecia is defined as the progressive miniaturization of normal terminal hair follicles on the scalp under the influence of androgens. This process gradually transforms terminal follicles into intermediate and eventually vellus follicles, which produce short, thin, colorless, and barely visible hairs with a significantly reduced lifespan.
There are two main types of Androgenetic Alopecia: Male Androgenetic Alopecia (MAGA) and Female Androgenetic Alopecia (FAGA).
- Male Androgenetic Alopecia (MAGA)
In 98% of men experiencing hair loss, the cause is Male Androgenetic Alopecia—commonly known as male pattern baldness. The remaining 2% suffer from temporary hair loss or hair loss due to an underlying condition, which can be reversed once the condition is treated.
In men, AGA typically begins as a symmetrical recession of the frontal hairline in the temporal areas, forming the characteristic M-shaped pattern, followed by thinning at the crown (vertex). Over time, these two areas may merge, resulting in extensive or complete baldness, leaving only a horseshoe-shaped strip of hair around the sides and back of the scalp (temporo-occipital area).
In general, individuals who begin losing their hair in their second decade of life are more likely to experience extensive hair loss over time. In some men, the initial pattern of Male Androgenetic Alopecia (MAGA) may progress slowly, stabilizing until the late 30s or early 40s. Although hair density naturally tends to decline with age, there is no reliable way to predict which pattern a young man with AGA will follow or what the final stage of hair loss will be. Each case is unique and may evolve differently, regardless of the age of onset.
- Female Androgenetic Alopecia (FAGA)
Female Androgenetic Alopecia (FAGA) is by far the most common cause of hair loss in otherwise healthy women. It is considered the female counterpart of Male Androgenetic Alopecia, though with a less pronounced genetic and androgenic component. This is because only about 30% of women with FAGA have a systemic condition that leads to elevated androgen production.
In general, female pattern hair loss can occur under three main scenarios:
- In genetically predisposed women, due to the local action of androgens on the scalp—without systemic androgen excess
- As a result of acquired androgen excess, such as conditions that elevate testosterone or DHT
- Due to hormonal changes during menopause, when protective estrogen levels decline.
FAGA is defined as hair loss predominantly at the crown and top of the scalp, characterized by a reduction in anagen (growing) hairs and a progressive miniaturization of affected follicles. Women with FAGA typically show a decrease in hair shaft diameter (known as thinning), but rarely experience the extensive shedding and follicle miniaturization seen in male pattern baldness.
Importantly, women almost always retain their frontal hairline, even in more advanced stages of alopecia—a key difference from the male pattern.
In contrast to men—where the onset of Androgenetic Alopecia typically peaks in the third and fourth decades of life—women tend to experience two peak periods for the onset of Female Androgenetic Alopecia (FAGA): the third and the fifth decade. The extent of FAGA is closely linked to the age of onset. Women who experience early-onset FAGA are more likely to develop more advanced stages of hair thinning over time. Conversely, those with late-onset FAGA rarely progress to the same degree of alopecia as seen in early-onset cases.
- Alopecia Areata and Its Forms
Alopecia Areata affects approximately 1–2% of the population, primarily adults, though it can also appear in children and adolescents. It is an autoimmune disorder, meaning the body mistakenly identifies the hair follicles as foreign and attacks them, ultimately damaging or destroying them. This condition occurs in both men and women and can cause hair loss in any area of the body where hair grows. It is also commonly associated with other autoimmune diseases such as vitiligo, Hashimoto’s thyroiditis, Addison’s disease, and atopic dermatitis.
Although the exact causes of Alopecia Areata remain unknown, patients often attribute it to stress and anxiety, although scientific evidence is still lacking. Other potential triggers may include local trauma to the scalp, viral or bacterial infections, pregnancy, hormonal imbalances, chemical exposure, allergic reactions and seasonal changes.
Alopecia Areata typically presents as well-defined, round or oval patches of complete hair loss, usually on the scalp or eyebrows. In some cases, it may appear as localized plaques of hair loss either on the scalp or elsewhere on the body.
There are several forms of Alopecia Areata, including:
- Diffuse Alopecia Areata: A less common form that presents as sudden, widespread thinning rather than patchy loss. It often occurs in individuals already suffering from Androgenetic Alopecia.
- Alopecia Totalis: The most extensive form, characterized by complete loss of hair on the scalp, as well as the eyebrows and eyelashes.
- Ophiasis: A distinct subtype in which hair loss occurs in a band-like pattern along the back of the scalp, stretching from one ear to the other.
Each form of Alopecia Areata requires careful diagnosis and tailored treatment, with the course and outcome varying significantly from person to person.
- Telogen Effluvium
Telogen effluvium is classified as a non-scarring, temporary form of alopecia.
Under normal conditions, approximately 90% of scalp hair follicles are in the anagen (growth) phase, while about 10% are in the telogen (resting) phase. Telogen effluvium occurs when a significantly larger percentage of hair follicles—more than 20%—suddenly and prematurely enter the telogen phase. In this phase, the hair stops growing and is shed.
The causes of this abnormal shift into the telogen phase can include acute physical or emotional stress, hormonal imbalances, nutritional deficiencies, sudden weight loss, medication use, or other underlying triggers. In most cases, the lost hair will regrow. Once the underlying cause of the telogen effluvium is addressed, the hair follicles typically return to their normal growth cycle.
- Triangular Alopecia
Another non-scarring form of alopecia is Triangular Alopecia, which sometimes begins in early childhood (typically between 1–3 years old) as unexplained hair loss in the temporal regions of the scalp. However, it can also present much later in life.
The characteristic pattern of hair loss in Triangular Alopecia is thinning or complete absence of hair in the areas around the temples. If the hair loss is not complete, the remaining hairs in the affected area often become miniaturized and turn into fine, light-colored “vellus” hairs—essentially soft, non-pigmented fuzz. Regardless of the specific presentation, this is a localized and non-progressive form of alopecia.
The exact cause of Triangular Alopecia remains unknown to this day. However, it is now a treatable condition—either through medical therapy or, when necessary, with surgical intervention.
- Loose-Anagen Syndrome
Loose Anagen Syndrome is a condition that typically appears in childhood and gradually improves or even resolves over time. It is more common in girls and individuals with light-colored hair. During the anagen phase of the hair growth cycle—the active growth stage—hair strands are so loosely attached to their follicles that they can easily be pulled out without pain during combing or brushing. Due to this abnormal attachment, the affected hairs often fail to grow to normal length.
This syndrome usually does not require treatment, as the condition tends to improve with age. Many patients diagnosed with Loose Anagen Syndrome experience spontaneous recovery by adulthood, with hair thickness and length returning to normal.
- Traction Alopecia
Traction Alopecia is caused by chronic pulling or tension on the hair and is most commonly observed in women who frequently wear hairstyles that tightly pull the hair. It typically appears along the front hairline, where the hair begins at the forehead.
Men who use hairpieces or wigs that are attached to existing hair may also develop this type of permanent hair loss if the hairpiece remains fixed in the same position for an extended period.
- Trichotillomania
Trichotillomania is a form of Traction Alopecia but is classified within the broader spectrum of obsessive-compulsive disorders, as it closely resembles compulsive behaviors. It is a psychological condition characterized by the pathological, compulsive pulling (plucking) of hair from the scalp or other hairy areas of the body, such as the eyebrows (a common cause for eyebrow transplantation).
In its milder form, trichotillomania manifests as the pathological pulling of hair while reading or watching television. In more severe cases, it becomes a ritualistic behavior, with hair pulling often occurring in front of a mirror. Individuals suffering from trichotillomania frequently experience feelings of guilt about their “unusual” behavior and attempt to conceal it.
Since trichotillomania is often a chronic condition, persistent hair pulling from the scalp or other areas may lead to bald patches—permanently hairless spots. In long-standing cases, trichotillomania can result in permanent Traction Alopecia or cause irreversible damage to the scalp skin, leading to permanent scarring alopecia.
It remains unclear whether this disorder should be classified simply as a “bad habit” or as a true compulsive behavior. Nevertheless, its management falls under the specialty of psychiatry, and assessment by a mental health professional is essential.
- Scarring Alopecia
Scarring alopecia accounts for approximately 3% of irreversible hair loss cases, characterized by the permanent destruction of hair follicles and subsequent scar formation. This condition encompasses a group of disorders where hair follicles are permanently destroyed and replaced by fibrous tissue. Hair regrowth is prevented due to the destruction of the epithelial stem cells responsible for follicle regeneration.
When the cause of follicle destruction is internal—such as various dermatological and inflammatory skin diseases—this condition is classified as primary scarring alopecia. Conversely, if external factors such as burns, trauma, radiation, or similar injuries are responsible, it is referred to as secondary scarring alopecia. In secondary cases, although hair loss remains irreversible, the follicle damage is a collateral effect rather than a direct target.
Furthermore, traction alopecia can, over time, lead to scarring and permanent hair loss if the chronic pulling persists. Similarly, trichotillomania, when prolonged, may cause permanent scarring in affected scalp areas due to repeated hair-pulling.
What Type of Alopecia Do I Have?
The question, “What type of alopecia do I have?” is one of the most common concerns among individuals experiencing thinning hair or hair loss. The answer is not always straightforward, as there are various types of alopecia, each with distinct symptoms, causes, and treatment approaches.
Diagnosing alopecia requires a clinical examination by a dermatologist or hair specialist who will assess the scalp, hair density, and the pattern of hair loss (e.g., diffuse, alopecia areata, androgenetic, scarring alopecia). They will also investigate potential underlying causes such as hormonal imbalances, iron deficiency, or significant stress.
Early identification of the specific type of alopecia has been shown to lead to more effective treatment and a faster resumption of hair growth. If you notice hair loss lasting longer than six months, it is crucial to consult a specialist to determine the most appropriate treatment for your case.
Timely Diagnosis and Treatment for Better Alopecia Resolution Outcomes
If you are experiencing hair loss, the only qualified professional to identify the underlying causes and design the optimal treatment strategy is a physician experienced and specialized in hair transplantation and hair loss therapies.
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