Diagnosing hair loss
Diagnosing hair loss


Whilst you may be sure your hair is thinning; a clinical definition of hair loss must be reached to determine the appropriate treatment.  Hair loss can be caused by  prescription medication, some types of infection, weight loss or inflammatory diseases like Crohn’s disease.

Your doctor, trichologist or dermatologist must first take a detailed medical history to determine;

  • Family history of hair loss
  • Current or recent infections
  • Recent surgery
  • Prescribed medications that could be contributing to your hair loss condition
  • Autoimmune conditions that can affect hair growth
  • Whether you may have postpartum hair loss
  • Whether you potentially have a hormone imbalance
  • Whether you are in an unusually stressful point in your life
  • Whether you have a vitamin or mineral deficiency or
  • Whether you have a medical condition such as diabetes or thyroid disease

Once a medical history is taken, the clinical features of your hair loss must be taken into account.


Clinical features differ depending on the type of hair loss you are experiencing.  Hair loss can occur as hairless lesions on the scalp or as a receding hairline.  In some cases, there can be abrupt shedding that ceases but where new hair fails to regrow.  To determine the appropriate treatment for hair loss, there are four main evaluations that can be used to assess hair loss type and to record progress.

The following tests can be used diagnose hair loss:

Hair pull test | This involves pulling a section of around 40-60 hair to establish how many are easily removed from the scalp.  If more than 10% of hair can be removed with a light tug this would be regarded as a positive result.  This would signal to the practitioner that a higher number of hairs than normal are in the ‘resting’ phase.  This type of test is normally used to diagnose telogen effluvium or diffuse hair loss.

Scalp biopsy | This procedure is usually carried out by a dermatologist and can identify high numbers of antibodies and white blood cells around the hair follicle.  This is useful for determining hair loss is due to an autoimmune condition such as hair loss.  A scalp biopsy can also identify abnormal bacteria within the follicle that can restrict hair growth.  Scalp biopsies are stern used to identify hair loss conditions such as alopecia areata and scarring alopecia.

Blood tests | Blood tests are often used to determine whether hair loss is due to a vitamin or mineral deficiency or due to an androgen/estrogen imbalance.  A blood test can also pick up thyroid disorders or other inflammatory conditions.  Blood tests are good for confirming a diagnosis of androgenic alopecia and can also direct potential treatment of diffuse hair loss by pin-pointing issues such as iron deficiency or low folate levels.  Whilst blood tests are helpful it is important they are correctly interpreted or your blood test results may be misleading.

Trichograms | A trichogram is a technique of evaluating how many hairs are in the growing phase, it can also determine differences in the width of hair follicles in different areas of your scalp.  This method of evaluation allows your practitioner to evaluate individual roots that are at different stages in the hair growth cycle.  This diagnostic method is good for diagnosing early stages of androgenic alopecia or chronic telogen effluvium.

Examination with a dermascope | This simple examination can pick up ‘exclamation mark’ hairs that are characteristic in the early stages of alopecia areata.


Blood tests are the single highest volume medical activity, making it prudent to ask how well a given test result (that is high, low, or normal) can define the health status of an individual who is suffering from hair loss.

Blood is a connective tissue and a conduit for many nutrients, hormones, proteins and minerals, but it can not give any indication of the levels of vitamins, minerals or haemoglobin that is within the tissue of interest e.g., the hair follicle.  This means that even ‘normal’ results must be evaluated sceptically by a trichologist or doctor when hair loss occurs.


(and what to do about it)

VITAMIN B12 | One of the eight B vitamins involved in the metabolism of absolutely every cell in your body.  It used to be known as the “maturation factor” because all cells in the body require vitamin B12 to mature into fully functioning cells.

Early studies looking at the function of B12 showed that blood cells in the bone marrow that were initially deprived of vitamin B12 could mature within a few hours of exposure to B12.  This explains why some patients feel rejuvenated within days of their first B12 injection [1].

B12 levels in the blood tend to fall late in deficiency, meaning the deficiency will be present for possibly months before it is reflected in the blood.  In addition to this, new Chemiluminescence technologies measure total serum B12 although around 80% of B12 circulates in a biochemically inert form.

What to do: Testing for ‘active’ B12 rather than ‘total’ will give a clearer indication of available B12.

VITAMIN D | A study investigating the role of vitamin D in female hair loss showed a direct correlation with the levels of vitamin D and hair loss. Whilst vitamin D deficiency is classed at a value below 25 nmol/L, the study revealed that all the participants that took part in the hair loss group had levels of vitamin D below 75 nmol/L.  Low levels of vitamin D also correlate to low levels of zinc.  As zinc is a major indicator of haemoglobin, a complete CBC and zinc panel are recommended.  Low vitamin D also correlates with high levels of hepcidin.  Hepcidin inhibits uptake of iron contributing to anemia and iron deficiency.

What to do: If your vitamin D levels are below 75 nmol/L, you can supplement with vitamin D, until it is within the desired range.  Request a CBC and zinc panel from your doctor or trichologist.

FERRITIN | Ferritin is a blood protein that binds iron, essentially holding this highly reactive ion in storage. A ferritin test evaluates how much iron you have in storage and high or low results may, or may not, be cause for concern.  In normal circumstances, ferritin levels are a sensitive and accurate marker for iron status, but ferritin levels will increase in response to inflammation, complicating the diagnosis.

In simpler terms, if there are other factors present, such as chronic inflammation, infections or autoimmune disorders, the ferritin test result will be unreliable and will not give an accurate reflection of iron stores. Even moderate exercise caused an increase in plasma ferritin concentration, with the increase being greater as the intensity and duration of exercise increased.  This makes ferritin an unreliable biomarker for hair loss.

What to do: When investigating iron status, also look at serum iron and total iron binding capacity, and transferrin saturation.

ZINC | An essential trace element derived from the diet, and one of the most studied minerals in relation to hair loss.  Zinc is strictly regulated by the body and the concentration in the blood changes only slightly where there is insufficient zinc in the tissue in the body.  Low zinc in the tissue causes changes to specific metabolic pathways that reduce the physiological need for zinc.  The Triage theory predicts that essential proteins can resist low zinc for a longer period than non-essential proteins, like the proteins that make up the hair fibre.

Various studies show low zinc is a significant factor in alopecia areata via its role in immune regulation, androgenic alopecia via its role in reducing DHT, and in chronic telogen effluvium via its role in protein manufacture.  Zinc levels fluctuate throughout the day, a fasting, morning blood test will give the most reliable result.

What to do: Get a blood test for zinc, if your zinc levels are lower than 85 µg/dl, it is likely that your zinc levels are contributing to your hair loss condition.   Optimal blood zinc levels for hair growth are around 100 µg/dl.

CORTISOL | When we’re stressed, have irregular eating patterns or a lack of quality sleep, our adrenal glands produce a hormone called cortisol.  Cortisol inhibits the action of growth signals on hair follicles causing a shift from growth phase into resting phase and premature shedding.

High levels of cortisol in the body can also be a reaction to uncontrolled inflammation within the body.  To assess cortisol levels, often a saliva test or blood test is taken in the morning to assess whether cortisol is within the normal range: cortisol is always higher in the morning.  What is vitally missing with this kind of test is a follow up throughout the day to check that cortisol levels drop as they are expected to.

What to do: Get a 12-hour cortisol test that lets you collect saliva samples throughout the day, giving you an accurate representation of your cortisol levels.


Diagnosing your hair loss condition should be simple.  It can take a few weeks to complete a range of tests but usually the diagnosis will be definitive with a clear treatment plan.  More complicated types of hair loss or rare genetic hair loss conditions are best dealt with by a dermatologist that has specific experience with complex hair loss cases.

Blood tests are often offered to patients with hair loss and an overwhelming majority come back with inconclusive results.  With little in the way of definitive serum ranges and an inconsistency in patient findings, blood tests are not very sensitive in the diagnosing hair loss and offer little prognostic value.

One particular study was able to come up with a clear algorithm to determine types of hair loss which is very useful for medical practitioners.  Often hair loss happens for a number of reasons and patience is needed when embarking on any type of hair loss treatment plan as the results can take at least 3 months to be evident.


  1. B12 Deficiency: Still America’s #1 Missed Diagnosis – WholeHealth Chicago