Diseases that cause hair loss in men include male pattern baldness, autoimmune conditions, thyroid disease, scalp infections and nutrient deficiencies.
When clumps of hair start showing up in the shower or the hairline marches back faster than feels fair, one question comes up again and again: which diseases cause hair loss in men? Age, genetics and hormones matter, but a long list of medical problems can thin hair, trigger bald patches or speed up shedding.
This guide walks through those medical causes so you can spot patterns, know which signs deserve a quick visit to a doctor, and understand how treatment for the underlying disease often helps the hair as well. It does not replace care from your own doctor, but it gives you a clear map of the main conditions linked with hair loss in men.
Which Diseases Cause Hair Loss In Men? Main Groups
Which diseases cause hair loss in men? Most fall into a few big groups. Some conditions act directly on the hair follicle. Others change hormones, blood flow or the body’s immune system so hair sheds as a side effect. Broadly, doctors think in terms of patterned loss, patchy loss, diffuse thinning and scarring loss.
The table below lines up major disease groups, how hair tends to fall out, and other clues that often show up at the same time.
| Disease Group | Typical Hair Loss Pattern | Common Extra Clues |
|---|---|---|
| Androgenetic alopecia (male pattern baldness) | Receding hairline, thinning on crown, slow progression | Family history, onset after puberty, no scalp redness |
| Alopecia areata and other autoimmune disease | Round patches, sudden shedding, sometimes total loss | Nail pitting, other autoimmune illness, body hair loss |
| Thyroid disease | Diffuse thinning across scalp, brittle hair | Tiredness, weight change, feeling cold or hot, dry skin |
| Lupus and connective tissue disease | Patchy or diffuse loss, sometimes scarring areas | Joint pain, rashes, sun sensitivity, mouth ulcers |
| Scalp infections (ringworm and others) | Broken hairs, patches with scale or crust | Itch, soreness, swollen glands, contact with infected people |
| Sexually transmitted infections such as syphilis | “Moth-eaten” patches or diffuse thinning | Rash, sores, swollen glands, risk from unprotected sex |
| Telogen effluvium from illness or surgery | Sudden diffuse shedding two to three months later | Major infection, crash diet, hospital stay, new medicine |
| Nutrient deficiencies and chronic illness | General thinning, dull or brittle hair | Fatigue, pale skin, weight loss, change in appetite |
Not every man fits neatly into one row. A single person can have genetic male pattern hair loss and, at the same time, extra shedding from thyroid disease, low iron or a recent viral illness. That is why a careful history and scalp check matter so much in clinic.
Diseases That Cause Hair Loss In Men Explained
Androgenetic Alopecia (Male Pattern Baldness)
Male pattern baldness is by far the most common disease behind thinning hair in men. It is driven by a mix of genes and sensitivity to the hormone dihydrotestosterone (DHT). Hair on the temples and crown shortens its growth phase, becomes finer, and eventually stops growing. The classic picture starts with a receding hairline and a bald spot that slowly widens on the top.
Most men with this condition are otherwise well. There is no scalp itching or pain, and blood tests often come back normal. The pattern, age of onset and family history are the main clues. The American Academy of Dermatology lists androgenetic alopecia as the leading cause of male hair loss and notes that it can start as early as the late teens in some men on its hair loss causes page.
Alopecia Areata And Other Autoimmune Conditions
Alopecia areata is an immune disease in which the body targets the hair follicle by mistake. Hair drops out in well-defined circles or ovals, often over a short period. The skin in these patches usually looks smooth and normal, without scale or redness. In some men, the disease extends to form a band around the hairline, removes all scalp hair (alopecia totalis), or affects eyebrows and beard.
Alopecia areata often travels with other immune conditions such as vitiligo, autoimmune thyroid disease or type 1 diabetes. Flares can follow infections, strong stress or no clear trigger at all. In many cases hair regrows, but cycles of loss and regrowth are common. Treatments aim to calm the immune attack and include steroid injections, creams and newer targeted drugs under specialist care.
Thyroid Disease
Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) can cause hair to shed. Men may notice diffuse thinning across the scalp, with strands that feel dry, coarse or easy to break. Hair from eyebrows and body may thin as well.
Other signs often point toward the thyroid. These include tiredness, weight gain or loss, bowel changes, feeling cold or hot, and changes in heart rate. The British Thyroid Foundation notes that thyroid disorders can cause diffuse hair shedding and patchy loss through linked conditions such as alopecia areata in its hair loss and thyroid guidance. Blood tests for thyroid hormones and antibodies make diagnosis straightforward in most men.
Lupus And Other Connective Tissue Disease
Systemic lupus erythematosus and related connective tissue diseases can harm hair through inflammation in skin and blood vessels. Men may see patchy loss with red, scaly lesions on the scalp that later scar, or more even thinning across the whole head during flares.
Lupus seldom comes alone. Joint pain, mouth ulcers, chest pain on breathing, sun-triggered rashes and general fatigue often sit alongside the hair changes. Because scarring loss can be permanent, early treatment with immune-modulating medicine and strict sun protection helps protect remaining follicles.
Scalp Infections Such As Ringworm
Fungal infection of the scalp, often called ringworm even though no worm is involved, is another disease that causes hair loss in men. It tends to show up as circular or irregular patches where hair breaks off at the surface, leaving “black dots”, scale and redness. It can spread in barbershops, gyms, contact sports or shared hats and pillows.
Some bacterial infections and severe folliculitis can also damage follicles and lead to patchy scarring. Men with diabetes, immune suppression or close contact with infected children have higher risk. Diagnosis usually rests on scalp examination, scrapings for microscopy, and sometimes culture. Treatment uses prescription antifungal tablets and medicated shampoos, with attention to hygiene to stop re-infection.
Sexually Transmitted Infections Like Syphilis
Syphilis can cause a pattern of hair loss known as syphilitic alopecia. Hair may fall in irregular “moth-eaten” patches or thin more evenly over the scalp. Men can also lose hair on the beard, eyebrows and body. Because the patches look similar to other non-scarring hair loss, the infection can slip past doctors unless they think to test for it.
Other signs of syphilis include painless sores on the genitals or mouth, a widespread rash, patchy lighter or darker skin, swollen lymph nodes and, later on, serious complications that affect the heart and nervous system. Blood tests confirm the diagnosis, and treatment with antibiotics usually stops further hair loss, with regrowth over time.
Telogen Effluvium From Illness Or Surgery
Telogen effluvium is a shedding state triggered by stress on the body. High fever, major surgery, severe infection, crash dieting, strong emotional stress, new medicines and chronic liver or kidney disease can all push many follicles into the resting phase at once. Two to three months later, hair starts to fall out in handfuls when washing or brushing.
The scalp usually looks normal, with no bald patches and no change in the hairline, but the drain fills fast. The good news is that this type of hair loss tends to improve once the trigger settles and the body recovers. A doctor’s job is to search for hidden illness, adjust medicines where possible and reassure men that regrowth usually follows.
Nutrient Deficiencies Linked To Hair Loss
Hair is a fast-growing tissue, so it shows strain when the body lacks building blocks. Low iron stores, low vitamin D, low zinc, low protein intake and eating disorders all show up in studies of men with diffuse thinning. Chronic gut disease that limits absorption can have the same effect even when intake looks fine on paper.
In these cases hair loss rarely stands alone. Men may feel weak, short of breath on exertion, prone to infections or plagued by cramps and tingling. Blood tests check iron, ferritin, full blood count, vitamin levels and markers of gut and liver health. Treating the underlying problem and correcting deficiencies slowly improves density, though full regrowth can take many months.
How Doctors Work Out Which Disease Is Behind Hair Loss
Because so many diseases cause hair loss in men, doctors follow a stepwise plan. First comes a detailed history: when the shedding started, how fast it moved, any itching or pain, current medicines, recent infections, weight change or surgery. Family history of hair loss, thyroid disease, autoimmune illness and early heart disease also matters.
Next comes a close scalp and body exam. Doctors check the pattern of thinning, look for broken hairs, redness, scale, scars and nail changes, and gently tug groups of hairs to see how easily they come out. Depending on the findings, blood tests may include thyroid function, iron studies, vitamin D, kidney and liver markers, infection screens and immune tests. In tricky cases a small scalp biopsy under local anaesthetic gives a microscopic view of follicles and surrounding skin, which helps separate scarring from non-scarring causes.
Treatment Approaches For Disease-Related Hair Loss In Men
Treatment always starts with the underlying disease. For male pattern hair loss, options include topical minoxidil, oral finasteride and, in selected men, transplant surgery under specialist care. For alopecia areata and other immune causes, doctors often use steroid injections into patches, topical immunotherapy or newer tablets that act on the immune system.
Thyroid disease, lupus, scalp infections and syphilis each need targeted medicine: hormone replacement or suppression, immune-modulating drugs, antifungal tablets or antibiotics. Once those conditions are under control, shedding often slows and regrowth begins, though timing varies. Telogen effluvium and deficiency-related thinning usually respond to correcting triggers, balanced diet and time.
Across all these diseases, realistic expectations matter. Some forms of scarring alopecia leave permanent gaps where hair will not return. Other types go through flares and quiet spells. Honest conversations with a dermatologist help men understand which aims are possible: slowing loss, thickening remaining hair, filling limited patches or simply stopping things from getting worse.
When To See A Doctor About Hair Loss In Men
Shedding a few hairs on the pillow is normal. The signs below point toward a disease process where medical review makes sense. This table groups common warning signs with what they may hint at and the sort of help usually needed.
| Warning Sign | Possible Disease Type | Who To See First |
|---|---|---|
| Sudden round bald patches | Alopecia areata, autoimmune disease | Dermatologist or general doctor |
| Rapid diffuse shedding after illness | Telogen effluvium, infection, surgery | General doctor |
| Thinning with tiredness and weight change | Thyroid disease or other hormone problem | General doctor, then endocrinologist |
| Patches with redness, scale or pus | Fungal or bacterial scalp infection | Dermatologist or general doctor |
| Moth-eaten loss plus rash or sores | Syphilis or other sexually transmitted infection | Sexual health clinic or general doctor |
| Scalp scarring and tight shiny skin | Scarring alopecia, lupus, other connective tissue disease | Dermatologist promptly |
| Slow receding hairline with family history | Androgenetic alopecia | Dermatologist or hair clinic |
Urgent review is wise if hair loss comes with fever, night sweats, rapid weight loss, severe headaches, vision change or chest pain. These combinations can signal infections, blood disease or vascular problems that reach far beyond the scalp.
Daily Habits That Help Medical Treatment Work Better
Once disease causes have been addressed, daily habits still shape how the scalp behaves. Gentle washing, avoiding harsh heat styling, skipping tight styles that pull on the hair, and protecting the scalp from strong sun reduce extra strain. Men who swim in chlorinated pools do well to rinse hair soon after.
Steady, balanced meals with enough protein, iron-rich foods, whole grains, healthy fats, fruit and vegetables give follicles raw material to build new strands. Smoking cuts blood flow to the scalp and links with poorer outcomes in several hair loss studies, so cutting down or quitting helps both hair and general health. Regular movement, enough sleep and stress-management habits like breathing drills or light exercise help hormonal rhythms that shape hair cycles.
Above all, men should know that hair loss linked with disease does not reflect personal failure or weak willpower. A clear diagnosis, a realistic plan and steady follow-through with medical advice give the best chance of keeping the hair that remains and, in many cases, bringing back a good share of what has been lost.