Alopecia
Disease Details
Family Health Simplified
- Description
- Alopecia is a condition characterized by hair loss from the scalp or other parts of the body.
- Type
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Alopecia can refer to various types of hair loss disorders, including alopecia areata, androgenetic alopecia, and telogen effluvium, among others. The genetic transmission can vary depending on the specific type:
1. **Alopecia Areata**: This is an autoimmune condition characterized by sudden, patchy hair loss. It has a complex genetic basis, often involving multiple genes, and does not follow a simple Mendelian inheritance pattern. There is a higher likelihood of occurrence if there is a family history of autoimmune diseases.
2. **Androgenetic Alopecia**: Also known as male or female pattern baldness, this type is the most common form of hair loss. It has a strong genetic component and is typically inherited in a polygenic manner, meaning multiple genes contribute to the trait. It can be passed down from either parent, but the inheritance pattern is complex and not strictly Mendelian.
3. **Telogen Effluvium**: This type of hair loss is usually triggered by stress, hormonal changes, or other factors. It does not have a strong genetic transmission component compared to alopecia areata or androgenetic alopecia.
Different forms of alopecia can have different genetic transmission mechanisms, including complex and multifactorial inheritance patterns. - Signs And Symptoms
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Symptoms of hair loss include hair loss in patches usually in circular patterns, dandruff, skin lesions, and scarring. Alopecia areata (mild – medium level) usually shows in unusual hair loss areas, e.g., eyebrows, backside of the head or above the ears, areas the male pattern baldness usually does not affect. In male-pattern hair loss, loss and thinning begin at the temples and the crown and hair either thins out or falls out. Female-pattern hair loss occurs at the frontal and parietal.
People have between 100,000 and 150,000 hairs on their head. The number of strands normally lost in a day varies but on average is 100. In order to maintain a normal volume, hair must be replaced at the same rate at which it is lost. The first signs of hair thinning that people will often notice are more hairs than usual left in the hairbrush after brushing or in the basin after shampooing. Styling can also reveal areas of thinning, such as a wider parting or a thinning crown. - Prognosis
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Alopecia is a condition characterized by hair loss, which can affect the scalp or other parts of the body. The prognosis for alopecia varies widely depending on the type and underlying cause:
1. **Alopecia Areata:** An autoimmune disorder that causes patchy hair loss. Prognosis can be unpredictable; some people experience spontaneous regrowth, while others may have persistent or recurrent hair loss.
2. **Androgenetic Alopecia:** Commonly known as male or female pattern baldness. It's typically progressive but can be managed with treatments like minoxidil or finasteride.
3. **Telogen Effluvium:** Often a temporary condition caused by factors like stress, illness, or hormonal changes. Hair usually regrows once the underlying cause is addressed.
4. **Traction Alopecia:** Hair loss due to prolonged tension or pulling. This can be reversible if caught early, but chronic traction can lead to permanent loss.
The long-term outlook largely depends on the type of alopecia, the response to treatment, and the ability to manage contributing factors. Consulting a healthcare provider for a definitive diagnosis and personalized treatment plan is recommended. - Onset
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Alopecia refers to hair loss from the scalp or other parts of the body. The onset of alopecia can vary widely depending on its type. Generally, it can be abrupt or gradual:
- **Androgenetic Alopecia:** This type, also known as male or female pattern baldness, usually has a gradual onset and tends to begin in the late teens to early twenties for men and later in life for women.
- **Alopecia Areata:** This autoimmune condition can have a sudden onset, with hair loss occurring in small, round patches and potentially advancing to more extensive hair loss.
- **Telogen Effluvium:** This type often follows a triggering event (such as stress, illness, or medication change) and typically has an onset of hair shedding 2-3 months after the triggering event.
The natural course of alopecia can vary. Androgenetic alopecia tends to be progressive without treatment. Alopecia areata can be unpredictable, with spontaneous regrowth possible. Telogen effluvium is usually temporary, with hair regrowing once the underlying cause is addressed. - Prevalence
- Alopecia, particularly alopecia areata, affects approximately 0.1-0.2% of the global population at any given time. It is a common autoimmune disorder that can lead to varying degrees of hair loss on the scalp and elsewhere on the body.
- Epidemiology
- Alopecia affects people of all ages, genders, and ethnicities. The prevalence varies depending on the type of alopecia. Androgenetic alopecia, the most common form, affects up to 50% of men and women by age 50. Alopecia areata has a lifetime risk of approximately 2%. Its onset can occur at any age but is most commonly seen in people under 30 years old. While androgenetic alopecia tends to progress gradually over time, alopecia areata can have an unpredictable course with sudden hair loss and potential for spontaneous regrowth.
- Intractability
- Alopecia, particularly alopecia areata, can be challenging to treat and manage, but it is not considered entirely intractable. The response to treatment can vary widely among individuals, and some may experience significant hair regrowth, while others may have persistent or recurrent hair loss. Treatment options such as corticosteroids, minoxidil, and other therapies may help, but results are often unpredictable.
- Disease Severity
- Alopecia varies in severity depending on the type and individual case. It generally ranges from small, patchy areas of hair loss to complete baldness on the scalp or body. The impact on a person's life can be significant, affecting self-esteem and emotional well-being. Severity is typically assessed by evaluating the extent and pattern of hair loss.
- Healthcare Professionals
- Disease Ontology ID - DOID:987
- Pathophysiology
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Hair follicle growth occurs in cycles. Each cycle consists of a long growing phase (anagen), a short transitional phase (catagen) and a short resting phase (telogen). At the end of the resting phase, the hair falls out (exogen) and a new hair starts growing in the follicle, beginning the cycle again.
Normally, about 40 (0–78 in men) hairs reach the end of their resting phase each day and fall out. When more than 100 hairs fall out per day, clinical hair loss (telogen effluvium) may occur. A disruption of the growing phase causes abnormal loss of anagen hairs (anagen effluvium). - Carrier Status
- Alopecia is a condition related to hair loss. The term "carrier status" is not typically applicable to alopecia as the condition can arise from various causes including genetics, autoimmune diseases, and other factors rather than following a simple genetic carrier pattern like some other hereditary diseases. If you need specific information about a genetic form of alopecia, such as alopecia areata, the details may vary. Please provide more context or specify the type of alopecia if you need a more targeted answer.
- Mechanism
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Alopecia is characterized by hair loss, which can occur on the scalp or other parts of the body. The mechanisms and molecular pathways involved vary depending on the type of alopecia.
### Mechanism:
In general, alopecia can be classified into scarring (cicatricial) and non-scarring (non-cicatricial) types.
1. **Scarring Alopecia**: This involves the destruction of hair follicles and replacement with scar tissue, often due to inflammatory processes.
2. **Non-Scarring Alopecia**: This involves hair shedding without permanent follicle damage, commonly seen in conditions like alopecia areata, telogen effluvium, and androgenetic alopecia.
### Molecular Mechanisms:
Different types of alopecia have distinct molecular mechanisms:
1. **Androgenetic Alopecia (AGA)**:
- **Hormones**: Dihydrotestosterone (DHT), derived from testosterone by the enzyme 5 alpha-reductase, binds to androgen receptors in hair follicles, leading to follicular miniaturization and shorter hair cycles.
- **Genetics**: Genetic predisposition influences androgen receptor sensitivity and enzyme activity.
2. **Alopecia Areata (AA)**:
- **Autoimmunity**: T-cell mediated autoimmune response attacks hair follicles, particularly the anagen (growth) phase follicles, leading to their premature transition to the catagen (regression) phase.
- **Cytokines**: Elevated levels of pro-inflammatory cytokines such as interferon-gamma and interleukins (IL-2, IL-15) disrupt follicular immune privilege, facilitating autoimmune attack.
3. **Telogen Effluvium (TE)**:
- **Stressors**: Various stressors (illness, hormonal changes, medications) cause a large number of hair follicles to enter the telogen (shedding) phase prematurely.
- **Signaling Pathways**: Stress-related hormones like cortisol may play a role, although exact pathways are not fully understood.
4. **Scarring Alopecia**:
- **Inflammation**: Chronic inflammatory conditions localized to hair follicles lead to destruction and replacement by scar tissue.
- **Genes and Proteins**: Dysregulation in genes encoding keratin and cell adhesion molecules contributes to follicle destruction.
Understanding these mechanisms helps in diagnosing alopecia types and informing treatment approaches, such as hormonal therapies for AGA, immunosuppressants for AA, and addressing underlying stressors for TE. - Treatment
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Alopecia refers to hair loss, and treatment depends on the type and cause. Common treatments include:
1. **Topical Treatments**: Minoxidil (Rogaine) applied to the scalp can stimulate hair growth.
2. **Oral Medications**: Finasteride (Propecia) is a prescription pill for men that can slow hair loss.
3. **Steroid Injections**: Corticosteroids injected into bald patches can help treat alopecia areata.
4. **Topical Corticosteroids**: Creams or ointments to reduce inflammation.
5. **Light Therapy**: Also known as phototherapy, it can be used to stimulate hair growth.
6. **Hair Transplants**: Surgical option for more permanent results.
7. **Platelet-Rich Plasma (PRP)**: Injections using patient's own blood to stimulate hair growth.
8. **Lifestyle Changes**: Diet, stress management, and proper hair care can support overall treatment.
Consultation with a healthcare provider is crucial for tailored treatment. - Compassionate Use Treatment
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Compassionate use treatments and off-label or experimental treatments for alopecia may include:
1. **JAK Inhibitors**: Initially designed for conditions like rheumatoid arthritis, drugs such as tofacitinib and ruxolitinib have shown promise in treating alopecia areata through clinical trials and compassionate use programs.
2. **Platelet-Rich Plasma (PRP) Therapy**: This involves injecting concentrated platelets from the patient's own blood into the scalp, which can stimulate hair growth.
3. **Low-Level Laser Therapy (LLLT)**: Also known as cold laser therapy, this non-invasive treatment promotes hair growth by stimulating hair follicles with low-level lasers.
4. **Stem Cell Therapy**: Still in the experimental phase, this involves using stem cells to rejuvenate and stimulate hair follicles for regrowth.
5. **Clascoterone**: An androgen receptor inhibitor currently undergoing investigation for its potential use in treating conditions like androgenetic alopecia.
6. **Secukinumab**: An anti-IL-17A monoclonal antibody typically used for psoriasis, being explored for its efficacy in alopecia areata.
These treatments are not yet universally approved for alopecia and are often accessible through clinical trials or special programs due to their experimental status. - Lifestyle Recommendations
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Lifestyle recommendations for managing alopecia include the following:
1. **Healthy Diet**: Ensure a balanced diet rich in vitamins and minerals, particularly iron, zinc, and vitamins A, D, and E.
2. **Stress Management**: Practice stress-reducing techniques such as yoga, meditation, or regular physical exercise.
3. **Gentle Hair Care**: Use mild shampoos and conditioners, avoid excessive heat styling, and limit the use of harsh chemical treatments.
4. **Regular Check-ups**: Monitor your health with regular medical check-ups to catch any underlying conditions that could contribute to hair loss.
5. **Avoid Tight Hairstyles**: Refrain from hairstyles that pull on the hair, like tight ponytails or braids, to prevent further damage.
Implementing these changes can support overall hair health and potentially improve the symptoms of alopecia. - Medication
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Treatments for the various forms of hair loss have limited success. Three medications have evidence to support their use in male pattern hair loss: minoxidil, finasteride, and dutasteride. They typically work better to prevent further hair loss, than to regrow lost hair. On June 13, 2022, the U.S. Food and Drug Administration (FDA) approved Olumiant (baricitinib) for adults with severe alopecia areatal. It is the first FDA approved drug for systemic treatment, or treatment for any area of the body.
Minoxidil (Rogaine) is a nonprescription medication approved for male pattern baldness and alopecia areata. In a liquid or foam, it is rubbed into the scalp twice a day. Some people have an allergic reaction to the propylene glycol in the minoxidil solution and a minoxidil foam was developed without propylene glycol. Not all users will regrow hair. Minoxidil is also prescribed tablets to be taken orally to encourage hair regrowth although is not FDA approved to treat hair loss. The longer the hair has stopped growing, the less likely minoxidil will regrow hair. Minoxidil is not effective for other causes of hair loss. Hair regrowth can take 1 to 6 months to begin. Treatment must be continued indefinitely. If the treatment is stopped, hair loss resumes. Any regrown hair and any hair susceptible to being lost, while Minoxidil was used, will be lost. Most frequent side effects are mild scalp irritation, allergic contact dermatitis, and unwanted hair in other parts of the body.
Finasteride (Propecia) is used in male-pattern hair loss in a pill form, taken 1 milligram per day. It is not indicated for women and is not recommended in pregnant women (as it is known to cause birth defects in fetuses). Treatment is effective starting within 6 weeks of treatment. Finasteride causes an increase in hair retention, the weight of hair, and some increase in regrowth. Side effects in about 2% of males include decreased sex drive, erectile dysfunction, and ejaculatory dysfunction. Treatment should be continued as long as positive results occur. Once treatment is stopped, hair loss resumes.
Corticosteroids injections into the scalp can be used to treat alopecia areata. This type of treatment is repeated on a monthly basis. Oral pills for extensive hair loss may be used for alopecia areata. Results may take up to a month to be seen.
Immunosuppressants applied to the scalp have been shown to temporarily reverse alopecia areata, though the side effects of some of these drugs make such therapy questionable.
There is some tentative evidence that anthralin may be useful for treating alopecia areata.
Hormonal modulators (oral contraceptives or antiandrogens such as spironolactone and flutamide) can be used for female-pattern hair loss associated with hyperandrogenemia. - Repurposable Drugs
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Repurposable drugs for alopecia include:
1. **Minoxidil**: Originally used as an antihypertensive medication, it is now commonly used for hair growth in both men and women.
2. **Finasteride**: Initially developed to treat benign prostatic hyperplasia, it is also used to treat male pattern baldness.
3. **Dutasteride**: Similar to finasteride, it was meant for prostate enlargement but has shown effectiveness in treating hair loss.
4. **Spironolactone**: Primarily a diuretic, it has anti-androgen effects that can help with female pattern hair loss.
5. **Tretinoin**: A derivative of vitamin A, used traditionally for acne and skin conditions, can enhance the absorption of minoxidil.
6. **Cyclosporine**: An immunosuppressant that has been observed to stimulate hair growth in some cases.
These drugs, originally intended for other medical conditions, have shown varying degrees of effectiveness in the treatment of different types of alopecia. - Metabolites
- Metabolites linked to alopecia include dihydrotestosterone (DHT), which is a key androgen influencing hair loss, as well as cortisol, which is related to stress-induced hair loss. Other relevant metabolites may include various amino acids, fatty acids, and inflammatory markers that affect hair follicle health.
- Nutraceuticals
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Nutraceuticals for alopecia primarily focus on providing essential nutrients that support hair health and growth. Common ingredients include biotin, zinc, vitamins (like vitamin D and E), and omega-3 fatty acids. Additionally, some nutraceuticals might contain plant extracts like saw palmetto and green tea, which are thought to inhibit the action of hormones that contribute to hair loss.
Nanotechnology, or "nanon," in the context of alopecia, refers to the use of nanoparticles to improve the delivery and absorption of therapeutic agents. This technology can enhance the effectiveness of treatments like minoxidil and other hair growth agents by allowing them to penetrate deeper into the scalp, potentially increasing their efficacy and reducing side effects. Nanoformulations can also be used to deliver vitamins and antioxidants directly to hair follicles, promoting better hair health and growth. - Peptides
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Peptides are short chains of amino acids that can promote hair growth by enhancing cell signaling and stimulating follicle activity. They are sometimes used in topical treatments for alopecia to strengthen hair and reduce hair loss. However, the effectiveness of peptides in treating alopecia can vary depending on the individual and the specific type of alopecia.
Nanotechnology, denoted as "nan," refers to the manipulation of matter on an atomic or molecular scale. In the context of alopecia, nanotechnology can be used to create nanoscale drug delivery systems that improve the penetration and efficacy of topical treatments. This can enhance the absorption of active ingredients like minoxidil or peptides directly into the hair follicles, potentially improving outcomes in treating alopecia.