Why am I losing hair? A pattern-by-pattern checklist of the usual causes

Finding more hair on the pillow, in the shower drain or on your comb is unsettling, and the first question is almost always the same: why is this happening? The honest answer is that "hair loss" is not one condition. It is a symptom with many possible causes, and several can overlap in the same person. The good news is that hair loss usually leaves clues. Where it happens, how fast it happens and what came before it narrow the list a great deal ¹.

This checklist walks through the usual causes by pattern. It is general health education, not a diagnosis, and is meant to help you notice the right details before you see a doctor.

The short answer

• Gradual thinning over months or years, at the hairline, crown or parting, is most often pattern hair loss (androgenetic alopecia) ²³.
• Sudden, diffuse shedding two to three months after illness, childbirth, surgery, crash dieting or major stress is most often telogen effluvium ⁴.
• Round, smooth bald patches suggest alopecia areata, an immune condition ⁵.
• Thinning at the hairline or temples in people who wear tight styles suggests traction alopecia ⁶.
• Scaly patches, especially in children, can be a fungal scalp infection ⁷.
• Scalp pain, redness or shiny patches need prompt review, as some scarring conditions destroy follicles.
• Common checks include iron stores and thyroid function ⁸.

First, two questions that sort most cases

Before going through the causes, ask yourself two things.

Is this shedding, thinning or both? Shedding is about hairs falling out: clumps in the shower, hair all over the floor, a ponytail that feels lighter. Thinning is about density: more scalp showing under bright lights, a wider parting, a hairline that has moved. Many people have both, but one usually dominates.

Is it everywhere, or in a particular place? Diffuse loss across the whole scalp points one way; loss at the temples, crown, a single patch or along the line where hair is pulled points another.

Pattern 1: Slow thinning at the temples, crown or parting

This is the most common long-term pattern. In men, pattern hair loss usually starts with recession at the temples, often forming an M shape, and thinning at the crown. It tends to progress over years and often runs in families. Doctors grade it with scales such as the Norwood scale, explained in the Norwood scale ².

In women the pattern usually looks different: the parting widens and the top of the scalp becomes see-through, while the front hairline is largely kept. It may become more noticeable around menopause ³. Women may also have it alongside other causes, which is why a fuller check is worthwhile; see women's hair loss step by step.

Clues: gradual change over months to years, family history, hairs that become finer and shorter before disappearing.

Usual next step: a doctor can usually diagnose it by examination, sometimes with trichoscopy, a magnified scalp check (what trichoscopy shows). Treatment works best on follicles that are still producing hair, so earlier assessment matters.

Pattern 2: Sudden heavy shedding all over

If hair suddenly starts falling out in large amounts across the whole scalp, the most common explanation is telogen effluvium. Normally only a small share of hairs are in the resting phase at any time. After a shock to the body, many hairs switch into that phase together and fall out about two to three months later ⁴.

Common triggers include high fever (dengue and COVID-19 are familiar examples in Malaysia), childbirth, surgery, severe illness, rapid weight loss, crash diets, stopping or changing hormonal contraception, some medicines and major emotional stress. Because of the delay, people often do not connect the shedding to the event.

Clues: a clear trigger two to three months earlier, hairs with a small white bulb at the root, no bald patches.

Usual next step: a doctor will usually check for ongoing causes such as iron deficiency or thyroid problems. Once the trigger has passed, the shedding usually settles within about six months, and the hair gradually fills back in. If shedding continues for longer, it is worth looking again for an ongoing cause or an underlying pattern hair loss being unmasked. The guide to minoxidil shedding covers a different, treatment-related type of shedding, and postpartum hair loss covers the shedding after childbirth.

Pattern 3: Round, smooth bald patches

One or more round, smooth, completely bald patches that appear quickly are typical of alopecia areata. In this condition the immune system targets hair follicles. The skin usually looks normal, without scaling or scarring, and short broken hairs may be seen at the edge. It can also affect the beard, eyebrows or eyelashes ⁵⁹.

Clues: sudden patches, normal-looking skin, sometimes nail pitting, sometimes a personal or family history of other autoimmune conditions.

Usual next step: a doctor, often a dermatologist, can confirm the diagnosis and discuss treatment. Many small patches improve on their own, but more extensive cases benefit from specialist care.

Pattern 4: Thinning along the hairline, temples or where hair is pulled

Traction alopecia comes from repeated pulling on the hair. It is common in people who wear tight ponytails, buns, braids, extensions or weaves, and can also occur when a headscarf is pinned tightly in the same place every day. It usually affects the hairline, the temples and the area above the ears ⁶.

Clues: thinning that follows the line of tension, small bumps or tenderness after styling, a history of tight styles.

Usual next step: loosen and vary the style. Early traction alopecia often improves when the pulling stops, but years of tension can lead to lasting hair loss, so this is one cause worth acting on early.

Pattern 5: Scaly patches, broken hairs or a sore scalp

A fungal infection of the scalp, called tinea capitis, causes patchy hair loss with scaling, broken hairs and sometimes swelling or pus. It is most common in children but can occur in adults, and it needs oral antifungal medicine prescribed by a doctor ⁷.

Ordinary dandruff and seborrhoeic dermatitis cause flaking and itch but usually do not cause lasting hair loss on their own, though heavy scratching can break hairs. See dandruff for the difference.

Pattern 6: Hair loss with scalp pain, redness or shiny areas

A smaller group of conditions, known as scarring alopecias, cause inflammation that destroys follicles. Examples include lichen planopilaris and frontal fibrosing alopecia, in which the hairline gradually moves back, often with loss of the eyebrows ¹⁰¹¹.

Clues: burning, itching or tenderness; redness or scaling around hair follicles; smooth shiny skin where pores seem to have disappeared.

Usual next step: see a dermatologist promptly. The aim of treatment is to calm the inflammation and protect the hair that remains, so early diagnosis matters.

Pattern 7: Diffuse thinning with other symptoms

Sometimes hair loss is one part of a wider health problem.

• Iron deficiency is common in women with heavy periods, after childbirth, in vegetarians and in people with some gut conditions. It can cause tiredness and paleness as well as hair shedding ¹².
• Underactive thyroid can cause tiredness, weight gain, feeling cold and dry hair; overactive thyroid can cause weight loss, a racing heart and anxiety. Both can affect hair ¹³¹⁴.
• Polycystic ovary syndrome (PCOS) can cause irregular periods, acne, excess body hair and thinning scalp hair ¹⁵.
• Medicines such as some blood thinners, retinoids, some antidepressants and others can trigger shedding, and chemotherapy can cause rapid hair loss ¹⁶¹⁷.

Usual next step: tell the doctor about all symptoms and medicines, not just the hair. Do not stop a prescribed medicine on your own.

Pattern 8: Patchy, irregular loss with broken hairs of different lengths

Trichotillomania is a condition in which a person feels a strong urge to pull out their hair, often without fully noticing. It leaves irregular patches with hairs broken at different lengths. It is more common than people think and is treatable with the right support, including behavioural therapy ¹⁸.

A quick checklist table

Before you see a doctor

Bring a short note covering when it started, what changed two to four months before, your medicines and supplements, family history, styling habits and any other symptoms. Take photos of the parting, crown and hairline in the same light so change can be measured over time. The guide to what happens at a hair loss consultation explains what to expect.

Common mistakes

• Assuming it is "just stress" without checking. Stress can trigger shedding, but iron, thyroid and pattern hair loss are common and checkable.
• Changing shampoos repeatedly. Shampoo rarely causes hair loss and rarely fixes it, though medicated shampoos help scalp conditions.
• Buying supplements blindly. Supplements help when there is a true deficiency; extra vitamins without a deficiency have little proven benefit.
• Waiting years with gradual thinning. Treatments for pattern hair loss work best when started early.
• Stopping a medicine because of shedding without talking to the prescriber.

Hair loss in Malaysia: local triggers worth noting

Dengue fever and other high fevers are a common trigger for shedding two to three months later. Hot, humid weather does not cause hair loss, but sweating under helmets and headscarves can aggravate scalp itch and dandruff. Tight daily styles for school, work or uniformed jobs can cause traction along the hairline. And because many people try salon treatments first, it is easy to lose months before a proper medical check. If the pattern is unclear, a general practitioner or a dermatologist registered with the Malaysian Medical Council is a sensible first step ¹⁹.

The bottom line

The shape of hair loss is your best clue. Gradual thinning in a typical pattern, sudden diffuse shedding after a trigger, round bald patches, loss where hair is pulled, scaly patches and loss with scalp pain each point to different causes and different next steps. More than one can happen together, so a careful history, a scalp examination and simple blood tests often give a clearer picture than months of trial and error. Note the pattern, take photos and get it checked early.

Frequently asked questions

What is the most common cause of hair loss?

Pattern hair loss (androgenetic alopecia) is the most common long-term cause in both men and women. In men it usually shows as a receding hairline and thinning crown; in women as a widening parting with the front hairline kept.

How do I know if it is shedding or thinning?

Shedding means more hairs falling out than usual, often in handfuls in the shower. Thinning means less density over time, seen as more visible scalp. The two can happen together, and photos taken a few months apart help tell them apart.

Can stress really make hair fall out?

Yes. A major physical or emotional stress can push many hairs into the resting phase at once, and they shed about two to three months later. This is called telogen effluvium and usually settles within about six months once the trigger has passed.

What blood tests are usually done for hair loss?

Doctors often check a full blood count, ferritin (iron stores) and thyroid function. Hormone tests may be added if there are signs such as irregular periods, acne or excess body hair.

Are round bald patches serious?

Round, smooth bald patches are often alopecia areata, an immune condition. They are worth showing to a doctor, especially if they spread, appear in the beard or eyebrows, or come with scaling, which may suggest a fungal infection.

Can hairstyles cause hair loss?

Yes. Tight ponytails, buns, braids and extensions pulled repeatedly can cause traction alopecia, usually along the hairline and temples. Caught early, loosening the style often helps, but long-term pulling can cause lasting damage.

When should I see a doctor about hair loss?

See a doctor if hair loss is sudden or heavy, comes in patches, is accompanied by scalp pain, redness or scaling, or comes with other symptoms such as weight change or tiredness. Gradual thinning is also worth assessing early, as treatment works best on hair that is still there.

Educational content. Not medical advice.