This post is for informational purposes only and should not be used in place of the advice of a medical professional.  

Medical Reasons for Hair Loss

Hair loss can be a distressing experience for both men and women. While genetics is often the main culprit behind hair loss, there are various medical conditions that can also contribute to it. It’s crucial to consult with a doctor to identify the underlying cause of hair loss, as many medical issues can be resolved, and hair growth can resume.

In this article, we will discuss 13 medical conditions that can lead to hair loss. We will also explore the hair growth cycle, types of hair loss, and common causes of hair loss such as aging, hormonal imbalance, and medication. By understanding the medical reasons for hair loss, you can take the necessary steps to address the issue and potentially regain your hair.

Key Takeaways:

  • Hair loss can be caused by various medical conditions, in addition to genetics.
  • It’s important to consult with a doctor to identify the underlying cause of hair loss.
  • Understanding the medical reasons for hair loss can help you take the necessary steps to address the issue and potentially regain your hair.

Hair Growth Cycle

To understand how certain health conditions can result in hair loss, it can be helpful to understand hair growth and its cycle. Your hair growth cycle is made up of four stages: anagen, catagen, telogen, and exogen. Any disruption along the growth cycle can cause hair loss.

Anagen Phase: This is when your hair actively grows from the root of a hair follicle. Blood vessels nourish the root, promoting hair growth. Certain medical conditions like androgenetic alopecia can disrupt this phase.

Catagen Phase: A brief transitional stage where hair growth begins to slow down.

Telogen Phase: During this stage, your hair is in a resting state, and shedding may occur. Telogen effluvium is a condition where more hairs enter this phase, leading to increased hair loss.

Exogen Phase: New hair growth pushes out old hair, starting the cycle again. Problems with the immune system or autoimmune diseases can affect these phases, causing bald spots or other types of hair thinning.

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13 Reasons for Hair Loss: Let’s Take A Look

Alopecia Areata

Medical Reasons for Hair Loss (Men and Women) - Alopecia

Alopecia areata is a type of autoimmune condition where your immune system mistakenly attacks hair follicles. This leads to hair loss in patches. Both men and women can be affected. It is most commonly seen in people between the ages of 30 and 60, and it is rare for children under the age of three to develop it.

Genetics might play a role, making individuals with a family history more susceptible. People with asthma, Down Syndrome, pernicious anemia, seasonal allergies, thyroid disease, and vitiligo may be more susceptible to developing alopecia areata.

While there is no cure, various treatments exist to help manage symptoms. Options include topical immunotherapy, anti-inflammatory drugs, and Minoxidil (Rogaine). Healthcare providers might also recommend medications to help with hair regrowth. Regular monitoring and consultations with your doctor can help you determine the best treatment plan for your needs.

Alopecia Areata Synopsis:

  • An Autoimmune Disorder
  • Seen in Both Males and Females
  • Hair Falls Out in Patches
  • Possible Genetic and Other Predispositions
  • Most Often Seen in Ages 30 – 60
  • Rare Before Age Three
  • Not Curable but Treatable
  • Hair Loss Permanent
  • Early Adult Onset
  • Adolescent and Childhood Onset is Rare


Diagnosis generally involves a physical exam, and your doctor might perform blood tests or a scalp biopsy to rule out other types of hair loss such as androgenic alopecia or tinea capitis caused by fungal infection.

Living with Alopecia Areata

Living with this condition can be challenging, both physically and emotionally. It’s important to seek support and educate yourself about the treatment options. Maintaining a healthy diet and managing stress can also help improve your overall well-being.

Scarring Alopecia

If you are experiencing hair loss due to scarring alopecia, it means that your hair follicles are being destroyed, which is replaced by fibrous or scar tissue. Unfortunately, the hair loss caused by scarring alopecia is permanent, and there is no known cure at this time. The goal of treatment is to prevent further hair loss. Scarring alopecia usually occurs in early adulthood, and it is rare in adolescents and children. Approximately 7% of patients seen at hair loss clinics experience scarring alopecia.

Scarring Alopecia Synopsis:

  • Destroys the Hair Follicles and Replaces Them with Scar Tissue
  • Hair Loss Permanent
  • Early Adult Onset
  • Adolescent and Childhood Onset is Rare

Anagen Effluvium

Medical Reasons for Hair Loss - Anagen Effluvium

Anagen Effluvium refers to sudden hair loss that happens during the anagen or growth phase of the hair cycle. This condition is commonly triggered by exposure to toxins such as chemotherapy drugs, radiation, and certain chemicals and poisons like Thallium, Boron, and Arsenic. Autoimmune diseases, such as alopecia areata, and infections are also potential causes.

Once the exposure to the cause is stopped, hair growth usually resumes.

Common treatments to help in the regrowth of hair include a topical minoxidil solution and scalp cooling during chemotherapy. It is important to note that hair shedding stops 3-6 months after chemotherapy has stopped. A change in the color and texture of new hair may occur.

Anagen Effluvium Synopsis:

  • Hair Shedding During Hair Growth Stage
  • Common Causes:
  • Autoimmune Disease
  • Chemotherapy
    • Stops 3 – 6 Months After Chemotherapy Has Stopped
  • Radiation
  • Exposure to Chemicals/Poisons – Such as Thallium, Boron, and Arsenic
  • Infection
  • Once Exposure to Cause is Stopped, Hair Growth Usually Begins
    • Change of the Color and Texture of New Hair Growth May Occur

Child Birth

Medical Reasons for Hair Loss (Men and Women) - Child Birth

If you’re a new mom, you may experience excessive hair shedding postpartum. This is a common occurrence caused by hormonal changes during pregnancy and childbirth. The body has higher levels of progesterone and estrogen during pregnancy, which causes hair to stay in the growth period of the hair growth cycle. Once birth occurs, these hormones shift to normal levels, and hair stays in the resting stage of the growth cycle for about three months and then begins to shed.

The hair loss seen postpartum isn’t actual hair loss; it is excessive hair shedding. This shedding is most dramatic three months postpartum and usually subsides 6-12 months after giving birth. It’s important to note that this shedding is temporary and should not be a cause for concern.

If you feel your hair shedding is beyond normal, consult a healthcare provider for possible treatments, including medical treatments, blood tests, and other treatment options. Healthy diet and managing emotional stress can also support hair regrowth.

Child Birth Synopsis:

  • Common and Usually Temporary
  • Most Dramatic 3 Months Postpartum
  • Subsides 6-12 Months Postpartum

Hormonal Imbalance

Medical Reasons for Hair Loss (Men and Women) - Hormone Imbalance

Hormones are chemical messengers that have a significant impact on various physiological activities in the body, including metabolism, growth, appetite, puberty, and fertility. Both men and women have estrogen, progesterone, and testosterone, but in different proportions. Men have higher levels of testosterone and lower levels of estrogen and progesterone, while women have lower levels of testosterone and higher levels of estrogen and progesterone.

Cortisol, also known as the stress hormone, can interfere with the hair growth cycle by affecting the cyclic regulation of the hair follicle during the hair growth cycle. Insulin, which regulates glucose levels in the bloodstream, is also thought to play a part in hair loss due to hormonal imbalance, but studies have not yet determined how or why.


Perimenopause and menopause naturally reduce estrogen and progesterone levels, which are female hormones. This decrease increases the impact of testosterone, a male hormone. When testosterone in hair follicles converts to DHT, hair follicles can become inactive, leading to hair loss.

Insulin Resistance

Insulin controls glucose in the bloodstream. Some studies suggest that insulin resistance may contribute to hair loss, though the exact mechanism remains unclear.

You might experience different types of hair loss like alopecia areata or androgenetic alopecia. A variety of medical conditions like thyroid disease or polycystic ovary syndrome can also lead to hair loss. Blood tests, scalp biopsy, and physical exams can help identify the causes. Telogen effluvium often results from hormonal changes or emotional stress.

Treatment options vary, but topical Minoxidil, platelets-rich plasma, and maintaining a healthy diet are common methods. Menopause-associated hair loss may be addressed with special hair products or birth control pills. If you experience patchy baldness like tinea capitis or sudden hair loss due to stress, quick action can help to prevent further hair loss.

Understanding your body’s hormone levels and managing them can maintain healthy hair follicles and promote new growth. Hormonal balance is key to preventing hair thinning and female-pattern baldness. A healthcare provider can offer effective treatments tailored to your needs.

Hair loss due to hormonal imbalance is reversible. The most commonly used treatment for hormonal hair loss is topical Minoxidil.

Hormonal Imbalance Synopsis: :

  • Cortisol
    • Stress Hormone
    • Affects the cyclic regulation of the hair follicle during the hair growth cycle.
  • Estrogen
    • A hormone found in higher levels in women than men
  • Progesterone
    • A hormone found in higher levels in women than men
  • Testosterone
    • A hormone found in higher levels in men than women.
  • Menopause
    • As women experience perimenopause and menopause there is a natural decrease in estrogen and progesterone (female hormones). With this, there is also an increase in the effects of testosterone (male hormone). Testosterone found in the hair follicles is converted into DHT (dihydrotestosterone) which is a hormone that can inactivate the hair follicles which then leads to hair loss.
  • Insulin Resistance
    • Insulin regulates glucose in the bloodstream
    • There are studies that suggest that insulin resistance contributes to hair loss, however, studies haven’t found the reason why or how.

Medical Treatments & Surgery

Medical Reasons for Hair Loss - Chemotherapy

Various treatments and surgeries can cause hair loss. For instance, chemotherapy and radiation, a common cancer treatment, can cause hair loss, but hair growth typically resumes after the treatment ends. This occurs as the body’s immune system heals and strengthens.

Hair loss after surgery typically lasts for 1-3 months, after which the hair will start to grow back normally. In the case of chemotherapy and radiation, hair growth typically resumes once the treatment ends, and the body begins to rebuild its immune system.

  • Chemotherapy
    • Regrowth usually starts 3-6 months after completing the treatment.
  • Radiation
    • Regrowth usually starts 3-6 months after completing the treatment.
  • Major Surgery
    • Hair shedding may increase within 1-3 months after surgery.
    • However, this typically reverses itself after a few months.

Medical Treatments & Surgery:

  • Chemotherapy
    • Regrowth starts 3-6 months after completion.
  • Radiation
    • Regrowth starts 3-6 months after completion.
  • Major Surgery
    • Increased Hair Shedding Within 1-3 Months After Surgery
    • Generally Reverses Itself After a Few Months

For hair loss induced by medical treatments, options like platelet-rich plasma therapy, medical interventions like corticosteroids, and hair transplant surgeries can help regrow hair and restore appearance. Always consider discussing treatment options with a healthcare provider to understand the best approach for your condition.


Medical Reasons for Hair Loss - Medication

Hair loss can be a side effect of certain medications. This type of hair loss usually occurs about three months after starting the medication. It is characterized by thinning hair on the top of the scalp, rather than patchy hair loss. The hair loss caused by medication tends to happen during the resting and growth phases of the hair cycle. When you stop using the medication, hair usually starts growing again within 3 to 18 months.

  • Amphetamines
  • Beta-Blockers
    • Propranolol (Inderal)
    • Metoprolol (Lopressor or Toprol XL)
  • Dextroamphetamine (for example, Dexedrine
  • Arthritis Medicines
    • Indomethacin
  • Birth Control Pills
  • Bipolar Medications
    • Lithium
  • Blood Thinners
    • Warfarin
    • Heparin
  • Chemotherapy
  • Gout Medicine
    • Allopurinol
    • Colchicine
  • Methamphetamine
  • Seizure Medicines
    • Valproic Acid
    • Carbamazepine
    • Trimethadione


Medical Reasons for Hair Loss - psoriasis

Psoriasis is a genetic autoimmune disease that causes itchy or sore patches of thick, dry, discolored skin known as plaques. The immune system, which usually attacks infectious germs, begins to attack healthy cells instead.

When psoriasis occurs on the scalp, it can lead to hair loss. While psoriasis doesn’t directly affect the hair follicles, the inflammation caused by scratching can loosen the hair follicle. There is no cure for psoriasis, but it can be treated and has been known to go into remission. Temporary hair loss is common and usually resolves when psoriasis is treated.

Psoriasis Synopsis:

  • Temporary
  • Usually Resolves When Psoriasis Is Treated


Medical Reasons for Hair Loss - Ringworm

Ringworm is a contagious fungal infection that mostly affects children. When it hits the scalp, it creates itchy, dry, and flaky bald spots. This infection, known as tinea capitis, leads to high levels of inflammation on the scalp and results in hair loss. As the fungus grows, it moves into the hair fibers, making them fragile and easy to break. If untreated, this process can cause permanent hair loss.

If left untreated, ringworm can cause permanent hair loss. Treatment usually involves antifungal medication.

Ringworm Synopsis:

  • Fungal Infection
  • Highly Contagious
  • More Common in Children
  • Bald Patches
  • Itchy and Scaly
  • Hair Loss May Be Permanent
  • Treatment – Antifungal Medication


Medical Reasons for Hair Loss - Syphilis

Syphilis is a highly contagious condition typically transmitted through sexual activity. Unlike many sexually transmitted diseases, it can cause patchy hair loss on the scalp, eyebrows, beard, and other areas if left untreated. This happens due to its impact on the hair’s growth cycle. This hair loss can mirror types seen in autoimmune diseases like alopecia areata or androgenetic alopecia. Once treated effectively, your hair will generally regrow as your immune system recovers.

Syphilis Synopsis:

  • If Hair Loss is Experienced It Usually Occurs in the Second Stage.
  • Treatable
  • Once the Immune System Recovers Hair Will Usually Grow Back

Telogen Effluvium

Medical Reasons for Hair Loss - Telogen Effluvium

If you’ve experienced a traumatic event, shock, or stress, you may have temporary hair loss known as Telogen Effluvium. This condition causes the hair growth cycle to go into resting for a period of time.

Blood tests and a physical exam are some ways your healthcare provider can diagnose this condition. Treatment options like topical minoxidil may promote new hair growth. The good news is that Telogen Effluvium usually resolves itself within 3 to 6 months, and hair growth usually begins again.

Telogen Effluvium Synopsis:

  • Caused by Trauma, Shock, or Stress
  • Temporary Hair Loss
  • Resolves in 3 to 5 Months
  • Treatable
  • Once the Immune System Recovers Hair Will Usually Grow Back


Medical Reasons for Hair Loss - Thyroid

The thyroid gland is responsible for releasing hormones into the bloodstream that play a prominent role in the development, growth, and metabolism of the body. When the thyroid’s hormonal process is not balanced correctly, it can cause many health issues.

Hypothyroidism, or an underactive thyroid, occurs when the thyroid doesn’t release enough hormones. Among other things, this can cause weight gain and hair loss. On the other hand, hyperthyroidism, or an overactive thyroid, occurs when the thyroid releases too much of the hormones. With hyperthyroidism, among other symptoms, you might see unintended weight loss, irregular heartbeat, and nervousness.

Fortunately, hair typically grows back once you receive appropriate treatment for the thyroid disorder. Treatment options may include medication to balance hormone levels, managing symptoms with other therapeutic approaches, or addressing potential underlying causes such as autoimmune conditions.

Regular blood tests and consultations with a healthcare provider can help monitor and treat thyroid problems effectively.

Thyroid Synopsis:

  • Hyperthyroidism – Overactive Thyroid
  • Hypothyroidism – Underactive Thyroid
  • Hypo and hyperthyroidism can cause hair to fall out
  • Involves Entire Scalp
  • In most cases, the hair will grow back once the thyroid disorder is treated

Vitamin Deficiency

Medical Reasons for Hair Loss - Vitamin Deficiency

If you are deficient in certain vitamins and minerals, it can lead to hair loss. Iron, Zinc, and Vitamin D are three essential nutrients that play a significant role in hair growth and maintenance.

  • Iron
    • Contributes to Hemoglobin Production: Hemoglobin in red blood cells carries oxygen and nutrients to hair follicles.
    • Oxygen Delivery: Without enough iron, hair cannot grow, leading to thinning and hair loss.
    • Dietary Sources: Include iron-rich foods like spinach, lentils, and red meat to aid in preventing hair thinning.
  • Zinc
    • Growth and Repair: Zinc plays a crucial role in hair tissue growth and repair.
    • Oil Glands Health: It helps keep the oil glands around hair follicles healthy, reducing hair loss and hair breakage.
    • Dietary Sources: Incorporate foods like oysters, pumpkin seeds, and cashews to combat zinc deficiency.
  • Vitamin D
    • Hair Follicle Stimulation: This vitamin is vital for stimulating new and old hair follicles, aiding in hair regrowth.
    • Stunted Growth: A lack of Vitamin D can lead to stunted hair growth, causing various types of hair loss.
    • Sources: Increase your Vitamin D intake through sun exposure, consuming fatty fish like salmon, or taking supplements.

Deficient levels of these essential nutrients can contribute to thinning hair and other forms of hair loss, such as telogen effluvium and alopecia areata. Ensuring a balanced diet rich in these vitamins and minerals can help mitigate these issues. For persistent hair loss, it’s important to consult with a healthcare provider to identify any underlying medical conditions.

Remember, a balanced diet rich in protein, iron, and other essential nutrients is crucial for maintaining healthy hair. If you are experiencing hair loss, it’s a good idea to consult with a healthcare professional to rule out any underlying medical conditions.

Vitamin Deficiency Synopsis:

  • Iron
    • Contributes to the Production of Hemoglobin
    • Hemoglobin Helps Deliver Nutrients and Oxygen to Hair Follicles
    • Without Enough Iron, Hair Won’t Grow
  • Zinc
    • Contributes to Hair Tissue Growth and Repair
    • Contributes to Healthy Oil Glands Around Hair Follicles
    • Hair Loss and Hair Breakage
  • Vitamin D
    • Stimulates New and Old Hair Follicles
    • If Deficient in Vitamin D, New Hair Growth Can Be Stunted


What are some common causes of hair loss in females?

Female pattern hair loss, which is a hereditary condition, is the most common cause of hair loss in women. Other causes include hormonal imbalances, such as those caused by pregnancy or menopause, as well as certain medical conditions such as thyroid disorders and PCOS. In addition, extreme stress or a traumatic event can also cause temporary hair loss.

How can hereditary hair loss be treated or managed?

Hereditary hair loss, also known as androgenetic alopecia, cannot be cured, but it can be managed. Medications such as minoxidil and finasteride can help to slow down or stop hair loss in some individuals. Hair transplant surgery may also be an option for those who wish to restore their hair. In addition, wearing wigs or hairpieces can help to improve the appearance of hair loss.

Can viruses cause hair loss in humans?

Yes, certain viruses can cause hair loss in humans. For example, the herpes simplex virus can cause hair loss in the area where the infection occurred. In addition, the varicella-zoster virus, which causes chickenpox and shingles, can also cause temporary hair loss.


Consult a doctor if you notice hair loss to find out the underlying cause. Hair loss causes like androgenetic alopeciatelogen effluvium, and alopecia areata are linked to numerous medical conditions. Treatments can vary from topical minoxidil to hair transplantsBlood tests and scalp biopsies help diagnose the issue.

Sometimes, restoring hormone levels or addressing nutritional deficiencies can promote hair regrowth. Your medical history, pattern of hair loss, and overall health will influence your treatment options. Make sure to discuss all these aspects with your healthcare provider.

If you have a personal story or experience with medical-driven hair loss, we would love to hear from you in the comments below.

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