Diagnosis of diseases that cause hair loss
Diagnosis of diseases that cause hair loss depends on which of the various types of hair loss diseases you are suffering from. There are many types of hair loss diseases and subtypes of officially recognized hair loss 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 types of hair loss 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 his hair loss disease, spot which type of hair loss diseases he is suffering from, 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 loss 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 patientís 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 tool that diagnoses hair loss diseases, 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 in hair loss diseases
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.