Pattern hair loss

Common type of hair loss affecting the scalp

Pattern hair loss
IMG-20190314-WA0000.jpg
Synonyms	Androgenic alopecia, androgenetic alopecia, male pattern baldness, female androgenic alopecia, female pattern baldness
Pronounce	N/A
Specialty	N/A
Symptoms	N/A
Complications	Psychological distress, reduced self-esteem
Onset	Gradual, usually after puberty
Duration	Chronic
Types	Male-pattern hair loss (MPHL), Female-pattern hair loss (FPHL)
Causes	Genetic predisposition, hormonal influences
Risks	Family history, aging, hormonal changes
Diagnosis	Clinical examination, dermatoscopy, scalp biopsy (if needed)
Differential diagnosis	Telogen effluvium, Alopecia areata, Scarring alopecia
Prevention	No proven prevention; early treatment may slow progression
Treatment	Minoxidil, Finasteride, Hair transplantation, Low-level laser therapy
Medication	Minoxidil, Finasteride (for men), Spironolactone (off-label for women)
Prognosis	Not life-threatening; progression varies by individual
Frequency	Affects ~50% of men and ~25% of women by age 50
Deaths	N/A

Pattern hair loss (also known as androgenetic alopecia) is the most common form of hair loss, primarily affecting the scalp's top and front regions.

• Male-pattern hair loss (MPHL): Characterized by hairline recession, vertex balding, or both.
• Female-pattern hair loss (FPHL): Typically involves diffuse thinning, particularly at the crown, without a receding hairline.

Clinical Presentation

Male-Pattern Hair Loss (MPHL)

• Begins with hairline recession at the temples and thinning at the crown (vertex).
• Progresses into a "Hippocratic wreath"—hair remains on the sides and back.
• Rarely leads to complete baldness.
• Classified using the Norwood-Hamilton Scale.

Female-Pattern Hair Loss (FPHL)

• Leads to diffuse thinning, mainly at the midline and crown.
• The hairline remains intact in most cases.
• Categorized using the Ludwig Scale (Grades I–III).
• Less likely to cause total hair loss compared to MPHL.

Causes and Risk Factors

Pattern hair loss results from a combination of genetics and hormonal influences, particularly androgens:

• Genetic predisposition – Strong hereditary link.
• Dihydrotestosterone (DHT) – A byproduct of testosterone, contributes to hair follicle miniaturization.
• Aging – Hair follicles become more sensitive to DHT over time.
• Other factors – Stress, nutrition, and health conditions (e.g., polycystic ovary syndrome in women).

Pathophysiology

Androgenic Influence

• Dihydrotestosterone (DHT) binds to androgen receptors in scalp follicles.
• This shortens the anagen (growth) phase and prolongs the telogen (resting) phase.
• Leads to progressive miniaturization—hair shafts become thinner and shorter.

Wnt Signaling Pathway

• Androgens may influence the Wnt signaling pathway, affecting hair growth and follicle cycling.

Androgens may interact with the Wnt signalling pathway, contributing to hair loss.

Diagnosis

Diagnosis is clinical and often based on:

• Patient history – Family history of baldness, rate of hair loss.
• Scalp examination – Assessing patterns of hair loss.
• Dermatoscopy (Trichoscopy) – Reveals miniaturized hairs and increased scalp visibility.
• Scalp biopsy (if needed) – Helps differentiate from other hair disorders.

Treatment Options

Management strategies depend on patient preference and treatment goals.

1. Medications

• Minoxidil (Rogaine) – Topical solution; promotes hair regrowth.
• Finasteride (Propecia) – Oral DHT blocker (for men only).
• Spironolactone – Off-label use in women with FPHL (anti-androgenic properties).

2. Surgical Treatments

• Hair transplantation – Moves DHT-resistant hair follicles from the back of the scalp.
• Scalp micropigmentation – Cosmetic tattooing to create an illusion of fuller hair.

3. Other Therapies

• Low-Level Laser Therapy (LLLT) – May stimulate hair follicles.
• Platelet-Rich Plasma (PRP) – Involves injecting growth factors to promote hair regrowth.

Epidemiology

• MPHL affects ~50% of men and FPHL affects ~25% of women by age 50.
• More common in Caucasians, less prevalent in Asians and Africans.

Prognosis

• Not life-threatening, but can impact self-esteem and mental health.
• Early intervention may slow progression and improve hair density.

See Also

• Alopecia areata
• Hair transplantation
• Scalp micropigmentation

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