What Illnesses Lead to Hair Loss? Symptoms and Treatments

Hair loss is very stressful, particularly when it’s part of an underlying health condition. Though some hair loss is normal, sudden, patchy, or extensive shedding might indicate a medical issue that needs to be addressed. 

Quick Overview: Illnesses that Can Cause Hair Loss

Illness/Condition	How It Causes Hair Loss	Symptoms	Is Hair Loss Reversible?
Alopecia areata	The immune system attacks hair follicles	Round bald patches	Sometimes, with treatment
Lupus	Autoimmune inflammation and scarring	Rash, fatigue, joint pain	Sometimes, depends on scarring
Thyroid disorders	Hormone imbalance	Brittle, thinning hair	Yes, if treated early
Cancer treatment	Chemotherapy and radiation damage	Hair falls in clumps	Usually, after treatment ends
Burning scalp syndrome	Inflammation or irritation	Tingling, burning, itching	Yes, once underlying cause is treated
Hormonal imbalance (PCOS, menopause)	Hormone level changes	Thinning, receding hairline	Yes, with treatment
Malnutrition /eating disorders	Nutrient deficiency	Dry, brittle hair	Yes, with proper nutrition

What Illnesses Cause Hair Loss?

Although there are a lot of health conditions that result in hair loss, some of the common illnesses include:

1. Alopecia areata

 Alopecia areata is an autoimmune disease in which the immune system attacks otherwise healthy hair follicles. It usually begins abruptly, forming relatively small, round or oval bald areas on the scalp, beard, or eyebrows. 

Occasionally, such patches are joined together to form significant bald areas. The nails also tend to be brittle in some instances. Corticosteroid injections, topical immunotherapy or minoxidil may stimulate regrowth, but the condition may recur.

2. Lupus

Lupus is a chronic autoimmune condition which may cause swelling on the skin, joints, and internal organs. Hair loss in lupus may be due to scalp inflammation or scarring. 

Individuals with lupus can also have fatigue, joint pain, and the so-called butterfly-shaped rash on the cheeks. Medications like hydroxychloroquine or steroids can treat lupus, and thus likely boost hair re-growth, but hair loss in scarred regions may remain permanent. 

3. Thyroid problems

Persistent thyroid problems, such as an overactive or underactive thyroid gland, may result in hair loss. You are more likely to experience hair loss if you have an underactive thyroid gland, as it may make your hair dry and brittle, and eventually cause hair breakage.

4. Cancer

Though cancer itself can cause hair loss, it is the chemotherapy that is primarily the cause of hair loss. 

During chemotherapy, multiple powerful drugs are given to kill the cancer cells in the body; however, while killing the cancer cells, the drugs also destroy the hair follicles. 

This causes the hair to fall slowly, often in large clumps. Other cancer treatments, such as radiation therapy or stem cell transplants, can also cause hair loss by damaging the cells that support hair growth.

5. Burning scalp syndrome

This condition causes tingling, burning, itching, or pain in the scalp. It can be an allergic reaction to a hair product or an indicator of other diseases that cause hair loss. It is yet unclear whether symptoms of burning scalp syndrome directly cause hair loss.

6. Hormonal imbalance or hormonal disorder

A hormonal disorder such as Polycystic Ovarian Syndrome can affect hair growth, leading to hair loss or baldness. Hormonal imbalance is also the cause of hair loss among women and men of all ages. 

For example, in women, menopause affects hair growth and thickness due to declines in oestrogen and progesterone levels. At the same time, in men, male-pattern baldness is caused by the conversion of testosterone into DHT in the scalp. 

7. Malnutrition and eating disorders

A deficiency of essential nutrients, such as vitamin B12, vitamin D, vitamin C, iron, and protein, can compromise the function of vital organs at the expense of hair growth. This can be aggravated by eating disorders such as anorexia, which leads to the hair being dry, brittle and likely to fall off. Hair usually grows back in 6 to 12 months, provided there is adequate nutrition and supplementation. 

What are the Symptoms of Hair Loss?

Depending on the underlying cause, hair loss can present in many ways and occur on the scalp or elsewhere on the body. Some of the symptoms or indications of hair loss are:

• Sudden loss of hair after combing, washing, or tugging.
• Thinning of hair on the scalp: Men develop a receding hairline on the forehead, while women develop a widening part or a receding hairline.
• Round or patchy bald spots on the scalp, beards, or eyebrows.
• Scalp patches with scales (usually associated with ringworm).
• Complete hair loss as a result of medical treatments like chemotherapy.

Whenever you notice sudden or patchy hair loss, you need to visit your doctor. It might indicate a serious underlying medical issue that needs to be addressed. 

Can Hair Loss Due to Illnesses Be Treated?

Treatment begins by treating the underlying condition. This could be as simple as medications to treat thyroid illness, immune-suppressing medications to treat autoimmune issues, or specific dietary changes to address deficiencies.

For hair regrowth, physicians can prescribe minoxidil to both men and women or finasteride in men. As an alternative, a hair transplant procedure (Follicular Unit Extraction [FUE], in particular) can provide a long-lasting solution when hair follicles are irreversibly destroyed.

Further loss can also be prevented by supportive care, such as gentle scalp hygiene and stress management.

Why Choose Treatment Rooms London 

In case your hair loss is associated with an illness, Treatment Rooms London offers individualised solutions.  Our expertise lies in high-end FUE hair transplants, which deliver permanent, natural results. Your treatment plan will be based on your health needs and hair goals, which are critical to our patient-first approach.

Illnesses that Can Cause Hair Loss FAQs

1. How safe is an FUE hair transplant?

It is minimally invasive, with minimal scarring and a very high success rate, leaving only tiny dot scars when performed by an experienced surgeon.

2. Do I need to see the doctor about my hair loss?

You should see a doctor if you have sudden and patchy hair loss or a family history of autoimmune diseases.

3. Can lupus cause hair loss?

Yes, lupus can inflame the scalp and skin, leading to discoid lesions that destroy hair follicles.

4. Will my hair regrow after chemotherapy?

Yes, your hair will regrow after chemotherapy, although it may have a different texture and colour at first.

5. What is the most common illness that causes hair loss?

Alopecia areata is the most common, although thyroid problems and PCOS also cause hair loss.

6. Is hair loss from illness always permanent?

Not always. Most cases are reversible after treatment of the underlying disease, although scarring and genetic causes may make loss irreversible.

References 

American Academy of Dermatology. (2025). Hair loss: Who gets it and what causes it, American Academy of Dermatology Association. Available at: https://www.aad.org/public/diseases/hair-loss/causes/18-causes (Accessed: 5 August 2025).

LloydsPharmacy Online Doctor. (2023). What illnesses cause hair loss?, reviewed 26 June 2023. Available at: https://onlinedoctor.lloydspharmacy.com/uk/hair-loss-advice/what-illnesses-cause-hair-loss (Accessed: 11 August 2025).

Mayo Clinic. (2024). Hair loss – Symptoms and causes. Available at: https://www.mayoclinic.org/diseases-conditions/hair-loss/symptoms-causes/syc-20372926 (Accessed: 7 August 2025).

National Health Service (NHS). (2024). Hair loss – Symptoms. Available at: https://www.nhs.uk/symptoms/hair-loss/ (Accessed: 11 August 2025).