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Introduction
For specific diagnostic markers please read the relevant material
for that particular condition.
There
are several hundred different types and subtypes of officially
recognized hair diseases that a dermatologist may have to consider.
As we learn more about genetics, molecular structure, and activity
of hair follicles, so current terminology will be refined and
expanded. The process of identifying new hair diseases continues.
Disease names that cover a range of different hair defect presentations,
such as telogen effluvium or alopecia areata, will be subdivided
into categories. New disease mechanisms will be identified and
given new names.
 However, most clinical dermatologists are unlikely to see more
than 20 key hair diseases during their careers. The most common
complaints a dermatologist encounters are; androgenetic alopecia,
alopecia areata, telogen effluvium, trichotillomania/traction alopecia,
Hair shaft defects from cosmetic processing, and excess hair growth
(hirsutism or hypertrichosis). The majority of identified hair diseases
are very rare occurring in less than 1% of the general population.
When a patient with a hair condition enters a clinic the dermatologist
is faced with making a specific diagnosis and prescribing a treatment.
Frequently I hear patients criticizing dermatologists for their
lack of understanding of their particular disease. However, because
of the limited research into hair diseases it is very difficult
to make a specific diagnosis and explain the diagnosis in detail
to the patient. Limited research also means that there are very
few diagnostic tests or treatments available, particularly for
diseases other than the most common ones listed above.
The result is that the dermatologist must define a disease and
appropriate treatment by a process of deduction from clues the
patient gives and fragments of information obtained in a physical
examination. A dermatologist resorts to three main methods of
information gathering. They will ask you questions about your
hair loss history and your lifestyle, they will conduct a visual
examination of your hair, and they may sometimes take samples
of hair, skin and/or blood for further testing and examination.
Some diseases are so obvious that a dermatologist knows exactly
what you have as soon as you come in the door. Male pattern baldness
is a good example. In these cases a dermatologist may forgo one
or more methods of information gathering and move straight to
discussing treatment options.
Hair
loss history and lifestyle
Dermatologists will ask a number of questions depending on what
they suspect you have. A dermatologist first needs to decide whether
the hair loss is congenital (present from birth) or acquired (hair
loss developed later in life). So the most obvious question will
be how long have you had the hair loss?
If the hair loss seems congenital then the dermatologist may ask
if other members of your family have similar hair loss and what
genetic relationship they are to you. They may ask about other hereditary
diseases in your family. They may ask if you had any physical or
emotional trauma during or shortly after birth. Using these and
other questions the dermatologist is trying to find out whether
the hair loss is based on genetics or on an environmental influence.
If the hair loss seems to be acquired later in life then the dermatologist
may ask a whole series of questions about the nature of the hair
loss.
- Does the hair progressively expand over time or does it wax
and wane?
- Does your family have a history of this type of hair loss?
- What do you do to your hair?
- How do you style your hair?
Questioning may expand to include other areas of your health and
lifestyle not directly connected with your hair.
- What other physical complaints are you being treated for?
- Do you feel healthy, depressed, fatigued?
- Do you have gastrointestinal problems?
- Any hormonal complications?
- Are you taking vitamin or mineral supplements?
The questioning may become quite detailed if the dermatologist
suspects an uncommon diagnosis.
Visual
examination
Many people expect a long and detailed examination as they are
used to for other complaints. However, hair and hair loss is clearly
visible. A dermatologist can gain all the information required by
examining the scalp for a minute or two.
The dermatologist first looks at the pattern of hair loss.
- Is it a limited focal patchy type of hair loss?
- Is it a diffuse pattern? Is the hair loss all over?
- Is hair loss limited to the top of the scalp, temples, occipital
area?
- Is it asymmetrical or symmetrical in appearance?
Next the dermatologist looks at the form of the hair loss.
- Does the hair loss involve inflammation?
- Is there any scar tissue?
- Is there any crusting or scaling of the skin?
- Are there any lumps and bumps in the skin?
- What does the hair look like?
- Is it healthy and shiny?
- Is it lackluster, thin?, straight, curly, kinked?
If the dermatologist suspects a fungal infection he/she may look
at your hair using a special light source called a wood’s lamp.
Under this light fungal material fluoresces and can be clearly identified.
As well as examining your hair the dermatologist may also examine
and ask you about the quality of your nails, teeth, and eyes. These
structures are all related to the hair follicle structure and can
occasionally be affected in some hair conditions.
Hair
pull test
The dermatologist may conduct a hair pull test. The dermatologist
gently tugs on a few strands of hair to see if the fibers pull out
easily or if they are firmly anchored in the hair follicle. Note.
If you suspect your dermatologist will physically examine your hair
the morning of a consultation you should not wash your hair!
When you wash your hair you remove many of the loose hairs. This
means that when a dermatologist does a hair pull test he/she may
obtain a false result. Not washing your hair will allow a more accurate
hair pull test to be made.
Hair
analysis
Sometimes a dermatologist may take a few hair fibers for microscopic
analysis. Usually the hairs have to be pulled or plucked out rather
than cut so that the dermatologist can examine the roots of the
fiber as well as the shaft. The hairs are placed on a microscope
slide and examined under the microscope.
Typically the dermatologist is asking himself/herself;
- Is the hair shaft straight and uniform thickness?
- Are there cracks, constrictions, or bulges along the length
of the hair fiber?
- Is the cuticle intact or deformed?
- Is the fiber twisted, knotted, kinked?
- Is the fiber cross section round, oval, grooved?
- Is the hair root healthy or malformed?
- Is the exposed end of the hair cut, frayed, broken?
- Are there any particles on the fiber that are not part of the
skin or hair structure?
- Are there mites, fungal structures?
- Using polarized light, does the hair fiber have a tiger stripe
look to it?
Sometimes a dermatologist may send the hair fiber away for further
analysis using a scanning electron microscope. These microscopes provide
very highly magnified images and the hair fiber can be processed so
that the surface of the fiber and the internal structure can be looked
at. Very occasionally hair fiber may be sent to a laboratory for chemical
analysis. Usually the most important analysis is to identify the concentration
of sulfur compounds in the hair fiber. Sulfur compounds are important
for strength and flexibility in the hair fiber. Hair may also be used
to look for concentrations of lead, zinc, copper, and various chemical
compounds.
Skin
scrapings and scalp biopsies
If the dermatologist suspects the hair condition may be the result
of bacteria, yeast, or fungi, he/she will take scrapings of skin
from the affected area. Some of these scrapings will be covered
with special staining chemicals that bind to certain types of bacteria
and fungi. Other scrapings may be used to culture any bacteria or
fungi that may be present. This will help define any particular
pathogenic strain that may be involved.
Sometimes a dermatologist needs to take a scalp biopsy. A biopsy
is a small piece of skin taken from the affected area. Typically,
a dermatologist will use a sterile, disposable biopsy punch. This
is simply a miniature cookie cutter that is pushed into the skin
and withdrawn pulling out a small piece of skin. The diameter of
the biopsy can be anywhere between 2 and 6 millimeters.
The piece of skin is then placed in a liquid that fixes and preserves
the material (usually a formaldehyde solution). The skin is then
sent to a histologist who cuts the biopsy into thin sections and
lays them on a microscope slide. The skin sections can be stained
in different ways depending on what the dermatologist wants to look
at.
The microscope slide may be examined by the dermatologist and
also by a pathologist. They look at the shape of the hair follicles
in the skin, their size and whether they are in a healthy state.
They also look for signs of inflammation, scarring, or infection
in the skin and around the hair follicles.
Blood
samples
Hair loss or excess hair growth can be a symptom of internal body
dysfunction. A dermatologist may suspect hormones or the immune
system to be involved in your hair condition. In this case he/she
may take a blood sample or ask you to see an endocrinologist/immunologist
for further testing.
With blood samples the dermatologist is considering such questions
as;
- What levels of estrogen and progesterone are present?
- What is the androgen concentration?
- What are the concentrations of thyroid hormones?
- What is the iron or copper concentration?
- How many lymphocyte cells or red blood cells are in the plasma?
- Are there any autoantibodies present and if so what do they
target?
While the questioning and examination are straight forward and do
not take long, they do provide enough information from which a dermatologist
can provide a diagnosis. With a diagnosis you can then progress to
considering any options for treatment.
Help
your dermatologist help you
The typical doctor/dermatologist appointment lasts no more than
seven minutes. That is not a lot of time for the dermatologist to
find out what the problem is and determine the future course of
action to take. The dermatologist’s priority is to diagnose
the problem and see the next patient. While you might want more
consultation time, frankly it is not going to happen especially
if you are in a country with a national health system. This means
that you have to be prepared and make sure you get the most out
of the appointment.
- First, make sure you keep the appointment! If you cannot then
please have the courtesy to inform the clinic. It is frustrating
when patients do not turn up. Your appointment could be used by
someone else rather than waste the time. It is also a waste of
money, ultimately your money through insurance and national health
charges!
- Write down a list of the medications you are using including
alternative medicines. Ideally, take the original packaging with
you in case the dermatologist needs more information about the
products.
- Make sure the clinic has details on other conditions you may
have and tell them about other doctors you are consulting with.
- If you have questions make sure you write them down and be ready
to ask. Take a pen and notepad to write down the answers the dermatologist
gives you in case you forget.
- Realize that with such a limited amount of time that the dermatologist
can only give you brief replies to your questions. Books and websites
like this one will give you more information.
- Realize not all questions can be answered. Hair research is
actually quite limited. We do not know the cause or mechanisms
of many hair diseases.
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