Illnesses That Cause Hair Loss

Illnesses and Conditions That Can Cause Hair Loss

While it is normal to lose around 50 to 100 hairs per day, losing noticeably more than that can sometimes be a sign of an underlying medical condition. Hair loss may be linked to genetics, hormonal changes, iron deficiency, thyroid problems, stress, medication use, autoimmune conditions, scalp inflammation, or infections. Before choosing any treatment, it is important to understand what is causing the shedding or thinning.

If you are still trying to understand the broader reasons behind shedding, our guide on causes of hair loss explains the most common non-surgical and surgical factors in more detail.

Some illness-related hair loss is temporary and may improve when the underlying condition is treated. Other types, such as genetic male or female pattern hair loss, may be progressive. A Turkey hair transplant may be considered only when the hair loss is stable, permanent, and suitable for surgical restoration after medical evaluation.

Alopecia

Alopecia is a general term for hair loss. The most common form is androgenetic alopecia, also known as male or female pattern hair loss. It is usually genetic and may appear as temple recession, crown thinning, diffuse thinning, or a widening part line depending on the patient.

Another form is alopecia areata, an autoimmune condition that may cause round or patchy bald spots. Traction alopecia can also occur when hair is pulled tightly for long periods through ponytails, braids, extensions, or similar hairstyles.

Pregnancy

Some women experience increased shedding during pregnancy or, more commonly, after childbirth. This is often related to changes in estrogen levels and the normal hair growth cycle. Postpartum shedding is usually temporary and may improve gradually within months.

However, if shedding is severe, prolonged, or combined with fatigue, heavy bleeding, low mood, thyroid symptoms, or nutritional problems, medical evaluation is recommended. In some cases, postpartum shedding can overlap with iron deficiency, thyroid imbalance, or female pattern hair loss.

Telogen Effluvium

Telogen effluvium is a common type of temporary diffuse shedding. It happens when a larger-than-usual number of hairs enter the resting phase of the hair cycle. Patients may notice more hair in the shower, on the pillow, or in the brush.

Common triggers include severe stress, sudden weight loss, surgery, high fever, thyroid disease, iron deficiency, childbirth, illness, and some medications. Telogen effluvium often improves when the trigger is corrected, but it can overlap with genetic hair loss.

Anagen Effluvium

Anagen effluvium causes rapid hair loss during the active growth phase of the hair cycle. It is most commonly associated with chemotherapy or radiation therapy, but it may also be linked to certain infections, toxins, or autoimmune conditions.

Hair loss may affect the scalp, eyebrows, eyelashes, or body hair. In many chemotherapy-related cases, hair can begin to regrow several months after treatment ends, although the timing and texture can vary between patients.

Iron Deficiency

Iron deficiency is one of the most important medical causes to evaluate in patients with diffuse shedding or weak hair quality. Low iron stores may affect oxygen delivery and follicle activity, especially in women with heavy menstrual bleeding, pregnancy, restrictive diets, or absorption problems.

Iron deficiency may be checked with blood tests such as hemoglobin, ferritin, serum iron, total iron-binding capacity, and transferrin saturation. If you want a more detailed explanation, review our guide on hair loss due to iron deficiency.

Hormonal and Thyroid Conditions

Hormonal changes can influence the hair growth cycle. Thyroid disease, PCOS, menopause, postpartum hormonal changes, androgen sensitivity, and DHT-related follicle miniaturization can all contribute to hair thinning or shedding in different ways.

Both hypothyroidism and hyperthyroidism may cause diffuse shedding, brittle hair, or changes in hair texture. Hormonal hair loss should not be treated blindly, because the right plan depends on the diagnosis. You can read more in our guide on hormonal effects on hair follicles.

Medication Side Effects

While chemotherapy is a well-known treatment that can cause hair loss, many other medicines may also affect hair follicles or the hair cycle. Blood thinners, antidepressants, beta-blockers, acne medications, cholesterol-lowering drugs, hormonal treatments, and other medications may contribute to shedding in some patients.

You should never stop a prescribed medication without speaking to your doctor. If hair loss began after starting a medication, your physician can review the timing and possible alternatives safely.

Ringworm and Other Scalp Infections

Fungal scalp infections such as ringworm, also called tinea capitis, can cause temporary hair loss, scaling, brittle hair, itching, redness, blisters, or patchy bald spots. These conditions should be evaluated by a doctor because treatment may require antifungal medication.

Not every itchy or flaky scalp is a fungal infection. Seborrheic dermatitis, psoriasis, eczema, folliculitis, and allergic reactions can also affect scalp health and worsen shedding or breakage. For scalp inflammation and dandruff-like symptoms, review our guide on seborrheic dermatitis hair loss.

Autoimmune and Inflammatory Conditions

Autoimmune diseases can sometimes affect hair growth. Alopecia areata may cause round patches, while conditions such as lupus or scarring alopecias may damage follicles if not treated early. Inflammatory scalp conditions can also cause redness, pain, scaling, or permanent follicle damage in more serious cases.

Sudden patchy hair loss, painful scalp symptoms, pus, severe scaling, or rapidly spreading bald spots should be evaluated by a dermatologist or medical professional.

How to Retain Healthy Hair

While hair loss can sometimes be a symptom of another illness or condition, there are still practical steps that can support hair and scalp health. A balanced diet with enough protein, iron, vitamin D, B12, zinc, healthy fats, and minerals may help support normal hair growth.

It is also helpful to reduce severe stress where possible, avoid very tight hairstyles, limit excessive heat styling, avoid harsh chemical treatments, and treat scalp itching, dandruff, or inflammation early. If shedding continues despite lifestyle changes, medical evaluation is the safest next step.

When Can Hair Transplant Be Considered?

A hair transplant is not the first solution for active illness-related shedding. If hair loss is caused by iron deficiency, thyroid disease, medication side effects, infection, scalp inflammation, or an autoimmune condition, the underlying issue should be diagnosed and treated first.

Hair transplant may be considered only when the hair loss pattern is stable, permanent, and suitable for surgical restoration. In suitable cases, reviewing transparent Turkey hair transplant cost and package details can help patients understand graft planning, technique, hotel, transfers, and aftercare together.