Hair Loss (Alopecia) symptoms and causes

Medically reviewed by:

Dr Sarah Marshall - Medical Officer

Updated: Aug 18, 2021

Next review: Aug 18, 2022

Hair loss can be distressing and have an impact on your self-confidence, but it is usually not something to be worried about.

Your hair goes through a life cycle that includes growth, rest and shedding phases. Losing up to 100 hairs a day is completely normal and often you won’t even notice it. Hair loss is part and parcel of getting older – more may fall out, or it may not grow at the rate that it used to.

Sometimes though, physical stress, a trauma or an illness can push more of your hair into the shedding phase of this life cycle, causing more hair loss than usual. In most cases, normal hair growth will return as your body recovers from the trauma, stress or illness and it will return to its normal thickness.

In other circumstances, hair loss can be a sign of an underlying condition, some of which we will cover further down the page.

If you are suffering from hair loss, you may notice:

Bald patches
A receding hairline
Hair thinning all over your head – you may notice your parting slowing getting wider
Sudden hair loss
Irritated or scarring patches on your scalp.

If your hair loss is accompanied by other symptoms, then this may indicate that there is an underlying illness, which you should seek treatment for.

If you are losing more hair than normal or have noticed thinning, it could be a caused by an underlying condition, such as:

This is temporary hair loss, where you lose more hair than normal. Usually, your hair thins all over your head, rather than just in one place and it will usually grow back over time.

The condition starts around one to three months after a stressful event – this could be surgery, a severe trauma, stress, a major life event or an illness. It is also very common in women who have just given birth, as their hormones start getting back to normal.

The most common type of hair loss in men is male pattern baldness. It is usually hereditary and will, most likely, affect all men at some point. At first, the hair begins to recede at the sides, and becomes thin on top, which will then develop into a bald spot. A rim of hair is often all that remains around the back and sides of the head, but sometimes this can thin too.

In women, a similar condition called female pattern baldness, or androgenetic alopecia or androgenic alopecia, is also believed to have a family link. However, the hair thins instead of receding like in men and is more common after the menopause.

Most people choose not to treat the condition, particularly men. However, some treatments are available, including medication, scalp surgery or wigs.

The most common form of aneamia is caused by an iron deficiency and can affect women and men. Aneamia can be diagnosed by a blood test and you can often take an iron supplement to address the deficiency. As well as hair loss, aneamia symptoms include headaches, fatigue, pale skin, cold hands and feet and dizziness.

Alopecia is caused by an overactive immune system, where the body attacks hair follicles by mistake. Alopecia can be unpredictable, with no pattern to the loss. Treatment is difficult but can include steroid injections or cream.

This can occur when taking supplements or medications that have vitamin A as an ingredient. Hair should grow back once you stop taking the supplement or medication. If you have been prescribed vitamin A, speak to a doctor before you stop taking it.

Vitamin supplements or a dietary change to include more meat, fish, non-citrus fruits and starchy veg can help if this is the cause of your hair loss. Your blood can be tested for this.

A low protein diet may cause the body to shut down hair growth. This often happens after two to three months of starting a low protein diet.

The thyroid gland produces a hormone called thyroxine, which controls the rate at which our bodies work. If it becomes underactive then symptoms such as hair loss, tiredness and weight gain are common. This is diagnosed with a simple blood test.

Dramatic stress on the body, such as losing a lot of weight in a short amount of time can cause hair loss.

PCOS is an imbalance of female and male hormones in a women’s body. If you have hair loss as well as other symptoms, such as weight gain, infertility, changes in menstrual periods or excess facial hair, then this could be attributed to PCOS. A change in diet, birth control pill and exercise can help, but it is best to seek advice from a doctor.

Chemotherapy is a treatment for cancer, which rapidly kills dividing cells, including both cancerous cells and hair cells, leading to hair loss all over the body.

Other causes of hair loss can include medication, such as:

Antidepressants
Blood thinners
Anabolic steroids
Trichotillomania – this is compulsive hair pulling and is a mental health disorder

This is not a full list - speak with a doctor for more advice.

Hair Loss (Alopecia)

Dr Sarah Marshall - Medical Officer

What is hair loss?

Symptoms

Associated conditions

Telogen effluvium

Male and female pattern baldness

Aneamia

Alopecia areata

High vitamin A consumption

Vitamin B deficiency

Low protein consumption

Hypothyroidism

Weight loss

Polycystic ovary syndrome (PCOS)

Chemotherapy