Medical Conditions That Can Cause Hair Loss

Hair loss can be caused by conditions inside the body, diseases that affect the scalp, medications, nutrient deficiencies, and the follicle's genetic response to hormones. The pattern, timing, scalp appearance, and associated symptoms help narrow the cause.

Do not self-diagnose based on shedding alone. Some conditions are temporary, while scarring alopecias can permanently destroy follicles without early treatment.

Thyroid disease

Both underactive and overactive thyroid function can contribute to diffuse thinning. Other symptoms may include fatigue, temperature intolerance, weight changes, heart-rate changes, constipation or diarrhea, and changes in skin or nails. Blood tests can evaluate thyroid function.

Iron deficiency and anemia

Low iron stores may contribute to shedding, especially with heavy menstrual bleeding, restricted diets, pregnancy, blood loss, or gastrointestinal disease. Testing should guide supplementation because iron can cause side effects and overdose is dangerous.

Autoimmune disease

Alopecia areata causes smooth patchy loss when the immune system attacks follicles. Lupus can cause nonscarring shedding or scarring scalp lesions. Other autoimmune diseases, including thyroid disease and vitiligo, may occur alongside alopecia areata.

Smooth patches, eyebrow loss, nail pitting, scalp scale, or inflammation deserve dermatologic evaluation.

Scarring alopecia

Conditions such as lichen planopilaris, frontal fibrosing alopecia, central centrifugal cicatricial alopecia, and discoid lupus create inflammation that can replace follicles with scar tissue. Warning signs include scalp pain, burning, itching, scale around hairs, pustules, and smooth shiny areas.

Early treatment aims to stop progression. Hair cannot regrow from a follicle that has been destroyed and scarred.

Major illness and telogen effluvium

Fever, infection, surgery, hospitalization, rapid weight loss, childbirth, and severe psychological stress can shift more follicles into a resting phase. Shedding often begins two to three months after the trigger, which makes the connection easy to miss.

Telogen effluvium often improves as the trigger resolves, but persistent or recurrent shedding needs investigation.

Polycystic ovary syndrome and hormonal conditions

PCOS can be associated with scalp thinning, irregular periods, acne, and increased facial or body hair. Evaluation may include menstrual history, physical examination, and laboratory testing. Pattern hair loss also occurs without PCOS.

Scalp infections

Tinea capitis is a fungal infection that can cause scale, broken hairs, patches, and sometimes painful inflammation. It usually requires prescription oral antifungal treatment because topical products alone do not reach the infected hair adequately.

Medications and medical treatment

Some anticoagulants, retinoids, anticonvulsants, antidepressants, blood-pressure drugs, hormonal therapies, and cancer treatments may contribute to hair changes. Do not stop a prescribed medication on your own. Ask the prescriber about timing, alternatives, and other causes.

Nutrient deficiency and excess

Inadequate protein, iron, zinc, or biotin can affect hair. Excess vitamin A or selenium can also contribute to loss. Restrictive diets and rapid weight-loss programs increase risk. Testing and dietary assessment are more useful than taking many high-dose supplements.

Read the key vitamins and minerals for healthy hair to understand deficiency-based supplementation.

Genetic pattern hair loss

Androgenetic alopecia is not an illness in the usual sense, but it is a common medical diagnosis. It typically causes a receding hairline or crown thinning in men and a widening part or diffuse central thinning in women. Evidence-based treatments work best when started before extensive miniaturization.

What a clinician may check

1. Timing and pattern of shedding
2. Scalp inflammation, scale, or scarring
3. Hair-shaft breakage versus root shedding
4. Medication, pregnancy, illness, and diet history
5. Targeted blood tests
6. Dermoscopic examination or scalp biopsy when needed

Track symptoms with monthly standardized photos and a timeline of health events. Our guide to hair falling out explains how to prepare for an appointment.

When to get prompt care

Seek early evaluation for scarring, pain, pus, rapid patchy loss, eyebrow loss, severe scalp inflammation, or symptoms of systemic illness. These are not situations to manage only with cosmetic products.

Noophoric Hair+ combines vitamins, minerals, botanicals, and amino acids to support fuller, stronger, healthier-looking hair. It is not a treatment for the medical conditions listed above.

Further reading

• Hair Loss in Men: Common Causes
• Postpartum Hair Loss

Sources

This article is educational and is not a substitute for individualized medical advice.