An overview on the diagnosis of the diseases that cause hair loss

information on hair diseases and their remedies
Home | Search | Resources | Site Map | Contact Us
Sponsored Articles

Home >> Overview of hair Diseases >> Diagnosis of Hair Diseases

Diagnosis of diseases that cause hair loss
Diagnosis of diseases that cause hair loss depends on the the type of hair loss you are suffering from. There are many possible types and subtypes of officially recognized hair diseases that a dermatologist may have to consider while diagnosing a patient. However in practice, most clinical dermatologists are likely to come across only about 20 hair diseases throughout their careers. Of these, just four will account for 95% the presentations of hair loss a dermatologist sees; pattern baldness, telogen effluvium, chemical overprocessing, and alopecia areata.

When a patient with a specific hair condition enters a clinic the first duty of the dermatologist is to diagnose and then prescribe treatments or hair care remedies. The most common method for diagnosis of hair loss diseases involves information gathering through questioning. Apart from questioning, use of diagnostic techniques like a hair pluck test can also help to identify diseases that cause hair loss.

Diagnosis of hair loss diseases through questioning
The first stage of diagnosis involves the process of deciding whether the diseases that cause hair loss are congenital, genetically inherited, or acquired. Congenital hair diseases means the diseases that are present from birth while a genetically inherited disease is one that develops later in life as a result of inherited genes. Acquired diseases are those that have developed as a result of the environment and its action on hair growth.

If the hair loss seems congenital then the dermatologist may ask a few questions related to the patient’s family back ground. For example; the dermatologist may ask whether other members of the family have similar hair loss diseases and what genetic relationship they are to you.

But if the disease that causes hair loss is acquired then the questions are directed to health and lifestyle.

The questioning step may become quite detailed if the dermatologist suspects an uncommon diagnosis.

Identifying hair loss diseases with diagnostic tools
The diagnostic tools like the hair pull test gives a rough idea about the quantity of hair that is being shed from the affected scalp. This pull test is done by grasping a lock of hair between the thumb and forefinger that contains around 50 hairs. A firm, steady traction is applied as the fingers are dragged along the length of the hair; no plucking is involved.

Mechanism of hair pull test
The number of hairs that are pulled out gives an indication of how many hair follicles are in a telogen resting state. Telogen hairs are easier to pull out than anagen growing hair. So in the pull test, telogen hairs will come out but the anagen hairs remain rooted in the scalp.

Normally, around 5 to 15 hairs can be pulled out from a normal scalp. More than 15 hairs suggests an increased number of hair follicles are in telogen. However, the hair pull test can be inaccurate as the number of hairs removed varies. It also depends on how long it was since the person washed their hair or how frequently they brush their hair. All these activities pull out telogen hairs. So if someone grooms their hair a lot, they will have less telogen hair in a hair pull test than someone who does not wash or comb their hair so much.

Hair pluck test
The hair pluck test is professionally known as trichogram. Here the objective is to pull a number of hairs from the scalp to examine their roots. It is generally done with rubber tipped tweezers that grasp about 50 hairs at a time. The pluck test can be painful for the individual but the pain is very brief as the hairs are plucked out. The hairs that are extracted by plucking are cut off from the upper part to remove the excess length. The cutting has to be done carefully in order to keep the root intact. The studied hair should only be of 1cm in length when measured from the root to upwards.

The severed hair is then floated in a wet microscope slide and a dye of 4-dimethylaminocinnamaldehyde is applied. This dye will stain only the hair roots that have intact internal root sheaths which are present only in anagen hairs. The telogen hairs will not be stained by the dye as it contains small, unpigmented, ovoid bulbs and are also devoid of intact internal root sheath. Under the microscaope, the dermatologist can count how many telogen and anagen hairs are present. The dermatologist can also look for any abnormal look to the roots of the hair fiber that might suggest a hair shaft defect.

Laboratory tests to identify the diseases that cause hair loss
If a patient has an unusual unexplained hair loss then various laboratory tests may be recommended. A potassium hydroxide test for fungal elements may aid in the diagnosis of infectious diseases that cause hair loss. This potassium hydroxide test is especially recommended for patients with localized hair loss.

Localized hair loss can be Alopecia Areata, but might be scalp ringworm. Some skin scraping taken from the scalp are placed on a slide, some potassium hydroxide is applied, and then the result is examined under a microscope to see if any fungi can be seen. A positive result confirms ringworm. Other tests may involve taking skin scrapings from the affected area and culturing them in the laboratory to find out what kind of bacteria or fungi are present. Other tests may be done on blood samples looking for inflammation, minerals, or viral infections.

Diagnosis of hair loss diseases through skin biopsy
Skin biopsies are done to confirm hair loss diseases like cicatrical alopecia. It also helps to find out the type of scarring according to which hair loss control treatments are decided.

A small skin biopsy of 2-4mm in diameter is taken from the scalp and processed for examination under a microscope. A pathologist or dermatologist will examine the intensity of destruction in the hair follicles, depth of the skin involved, and the presence and location of inflammation in relation to the hair follicles.

Most of the diagnostic procedures like questioning and laboratory tests are straight forward and do not take long. These tests provide ample information from which a dermatologist can usually identify the hair problem. In accordance to the diagnosis the treatment of hair loss disease is selected.

So remain informed about the various diagnostic procedures which will give you a clear understanding on the type and intensity of hair loss.

Edward A. Jackson, “Dermatology”, June 2000, Primary Care; Clinics in Office Practice, Volume 27, Number 2

  Copyright © Hair Diseases
Disclaimer | Copyright | Privacy Policy
Hair Diseases dot com