Hair loss: when should you see a doctor?

How Many Hairs a Day Is Normal

According to the American Academy of Dermatology, shedding 50 to 100 hairs a day is considered normal. This range is often seen as a threshold, but it is not a threshold; it is an average.

There are several reasons why this number is only a rough measure. Each hair has its own growth cycle; because the hairs are not all in the same phase at the same time, shedding is not spread evenly across the days. How often you wash or brush your hair, and whether or not you tie it up, can easily double the count for a single day. If your hair is long, the same number of hairs looks like more.

Counting itself is also less objective than it seems. Hairs shed on days when you do not wash your hair build up and end up being counted as a single day's loss; and the more attention you pay, the more hairs you collect. Once you start monitoring your shedding, there is no way to tell how much of any increase you see comes from your hair and how much from the way you are looking at it.

The real limitation is this: the number tells you how much hair you are losing, not why. Hair loss often points to underlying inflammation or to a problem with the hair cycle or the structure of the hair shaft. This is why it is recommended that the assessment be based on a medical history (your doctor asking you in detail about your symptoms and your past) and an examination of the scalp. In other words, the right question is not “how many hairs?” but “how, and together with what?”

Shedding and Thinning Are Not the Same Thing

Hair becomes sparser in two different ways, and the two do not look the same.

The first is increased shedding. In a condition called telogen effluvium, more hairs than usual end their growth cycle early, and the loss is spread across the whole scalp. This is the typical example of widespread shedding.

The second is thinning. In pattern hair loss (hair loss that follows a particular pattern), the main process is follicular miniaturisation, meaning the hair follicle gradually shrinks: with each cycle, the hair grows back a little finer, shorter and lighter in colour. In this case you may not see a striking increase in what collects in the bath drain; what changes is not the number of hairs you shed but the quality of the hairs that remain.

This distinction matters in practice, because someone who monitors themselves only by counting hairs can miss miniaturisation. The two can also occur together in the same person; it is the examination, not the count, that shows which one is dominant.

Sudden, Widespread Shedding

Heavy shedding that starts after a particular point in time and covers the whole scalp is one of the situations in which you should see a doctor. Here, the main aim of the assessment is to find out what triggered the shedding; a medical history and an examination of the scalp are used together for this.

However, not all widespread shedding is telogen effluvium. A subtype of alopecia areata (patchy hair loss) called alopecia areata incognita starts suddenly and progresses with marked shedding and widespread thinning; because it resembles telogen effluvium, it gets overlooked. It is diagnosed by assessing the clinical findings, trichoscopy (a magnified examination of the scalp and hair) and, when needed, histopathology (examining a tissue sample under a microscope) together.

This is also why the medical history looks back in time. Whatever started the shedding may not coincide with the day you noticed it. So at the consultation you are asked not only about the last few weeks but also about earlier events, such as illnesses you have had, operations, changes in medication and diet, and giving birth.

The American Academy of Dermatology states that excessive shedding often stops on its own. This is true; but the severity of the shedding does not tell you which shedding falls into this group. What distinguishes the two conditions is how the scalp and the hairs look on examination.

Scalp Redness, Scaling or Pain

If the symptoms come from the scalp rather than from the hair itself, the question to ask changes too. Itching, burning, tenderness, redness, scaling or pustules (pus-filled bumps) are signs in the scalp, not in the hair, and they point to inflammation.

Folliculitis decalvans and dissecting cellulitis of the scalp are among the conditions that cause scarring hair loss (cicatricial alopecia); both are defined by long-lasting inflammation and irreversible hair loss. Publications in this field stress that, because the two diseases develop through different mechanisms, distinguishing between them correctly determines the direction of treatment.

Redness does not always mean a scarring disease. In older age, tinea capitis, a fungal infection of the scalp, can be mistaken for other conditions: a review of patients aged 65 and over found that more than a third of them had initially been given a different diagnosis, such as seborrhoeic dermatitis (a greasy, scaly inflammation of the skin). A wrong diagnosis does not just waste time; it also leads to the wrong treatment.

If scalp symptoms come with the shedding, you should not wait as long before seeing a doctor. In this case, what needs to be assessed is the skin itself, not how the hair looks.

Patchy Hair Loss

A round or oval bald patch with clear edges, where the skin looks smooth, is the well-known appearance of alopecia areata. According to expert consensus, trichoscopy is necessary in this condition for diagnosis and follow-up; a biopsy (taking a small tissue sample) is considered when the cause of the hair loss remains unclear.

Telling one kind of patchy hair loss from another by looking in the mirror is not reliable, because other conditions also cause the same appearance. In one study, trichoscopy showed comma-shaped hairs in two patients thought to have alopecia areata; the diagnosis was corrected to tinea capitis (a fungal infection of the scalp), and the inappropriate steroid (corticosteroid) treatment was stopped.

This is why patchy hair loss, even a small patch, is a finding that needs to be examined. What matters is not the size of the area but how sharp its edges are and how the skin in that area looks.

Loss of Follicular Openings

One of the most important findings at an examination can be seen with the eye: the loss of the small openings in the scalp that hairs grow from (follicular openings). On a healthy scalp, these small openings can be made out even in an area that looks bald. If the openings have disappeared and the skin looks shiny and smooth, the situation is different.

Primary scarring (cicatricial) alopecias are a group of conditions in which the hair follicle is destroyed and replaced by fibrosis (hard connective tissue), causing irreversible hair loss. A scalp biopsy is regarded as the main tool for confirming the diagnosis.

The difference is this: losing a hair is not the same as losing the hair follicle. A hair that has fallen out can grow back as long as its follicle is still in place. A follicle that has been replaced by fibrous tissue does not come back.

You cannot assess this finding with certainty at home; magnification is needed to see whether the openings are visible. Even so, if a bald area looks smooth and shiny, has no broken hairs at its edges and is slowly getting larger, this is a reason to bring your consultation forward.

If redness and scaling around the hair follicles are seen together with loss of the openings, this is not a cosmetic issue but a question of dermatological diagnosis.

Why Time Is Critical in Scarring Alopecia

Lichen planopilaris is a type of scarring alopecia in which the immune system plays a role and which leaves permanent damage to the hair follicle. According to the European Academy of Dermatology and Venereology's expert group on hair disorders, early diagnosis and timely intervention are necessary to limit hair loss and slow the progression of the disease.

However, there is no known cure for the disease; its course and its response to treatment cannot be predicted, and randomised trials (comparative studies in which participants are assigned to groups at random) are limited. These two facts need to be considered together: the aim of acting early is not to bring back what has been lost but to limit the loss.

The extent of delay has also been measured. In a study of 53 patients with primary scarring alopecia confirmed by tissue examination, the median duration of the disease at the time the patients sought care was four years. Hair follicles lost during this time do not come back.

This is exactly what sets this condition apart from the others. With most types of hair loss, it is reasonable to watch for a while. But in an area where the follicular openings have disappeared, waiting means time during which the loss continues.

Crown Thinning in Women with a Preserved Hairline

Female pattern hair loss is a slowly progressing thinning that is concentrated particularly on the crown and the upper area on either side of it. The front hairline is usually preserved, and miniaturisation, meaning the shrinking of the hair follicle, is not as marked as in men.

Here, the preserved hairline gives a false sense of reassurance. Because the hairline is still in place when you look in the mirror, the problem is noticed late; often the first thing that stands out is that the parting is gradually getting wider. This is why, in this condition, it is the width of the parting that is monitored, not the number of hairs shed.

Diagnosis uses a combination of a medical history, an examination, tests that assess hair loss, dermoscopy (examination with a device that magnifies the skin) and, when needed, a scalp biopsy. If there are signs of hyperandrogenism, meaning an excess of male hormones, investigation for a disorder of the ovaries or adrenal glands is recommended.

In this condition, seeing a doctor early has a particular significance. Current treatments are considered to play a stronger role in stopping progression than in restoring density that has already been lost; this means that the point at which the problem is noticed affects the outcome. Which treatment may be considered is decided at the consultation.

Accompanying Systemic Symptoms

Hair loss is not always just a hair problem. In rheumatological diseases (diseases of the joints, connective tissue and immune system), hair loss can arise through mechanisms involving the immune system, hardening of the tissue and the blood vessels. Medicines being taken and accompanying autoimmune scalp diseases (in which the immune system targets the body's own tissue) also contribute to the picture. For this reason, a systematic assessment is recommended, made up of a symptom-focused medical history, a physical examination and, when needed, laboratory tests or a biopsy.

Tests commonly requested in the assessment include thyroid-stimulating hormone, a full blood count and iron studies; a scalp biopsy is used to confirm scarring hair loss.

In practice, this means that symptoms in your joints, your skin or your general health that start around the same time as the shedding take the assessment beyond the scalp. In this case, the question to ask is not how your hair will improve, but what the hair loss is a sign of.

What Is Checked at the Consultation

The assessment of hair loss begins with a medical history and an examination of the scalp. Your doctor weighs up three possibilities together: widespread shedding, loss limited to a particular area, and thinning that follows a particular pattern. Trichoscopy is widely used to tell these three apart; in one study, it was found to be a step that confirmed or corrected the initial clinical diagnosis.

The pull test is also part of this examination: a small bunch of hair is gently pulled and the number of hairs that come out is checked. But, like counting hairs, this test has a limitation too. A study that measured the force applied reports that the force varies depending on who performs the test, and that standardising it is still an unresolved issue. So the pull test provides information, but it cannot be used on its own to make a decision.

This is why the information you can prepare before your consultation relates to your medical history:

• When the shedding started.
• Whether it has been constant or has come and gone.
• Any medicines you started or stopped around that time.
• Illnesses you have had.
• Whether anyone in your family has had something similar.
• Whether you have itching, pain or scaling on your scalp.

You will be asked about all of these at the consultation, and they help guide the diagnosis.

In short, neither the count you make at home nor the result of a single test is a diagnosis. A diagnosis is made by assessing the medical history, the appearance of the scalp, trichoscopy and, when needed, laboratory tests and a biopsy together.

Treatments offered here

The clinic offers hair and skin mesotherapy treatments. This article does not make a diagnosis and cannot tell you which condition you have; it only explains which findings distinguish the conditions from one another.

If you have any of the signs above, the first step is not choosing a treatment but having your scalp assessed. You decide when to see a doctor based on which signs you have; the aim of this article is to show which findings to look at when making that decision.