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Home arrow Basics arrow Hair loss arrow Forms and causes
Forms of Hair loss and its Causes

There are different forms of hair loss (= alopecia), which can be divided into a number of subgroups. Loss of hair can have  a great array of causes: (a) metabolic disorders,  (b) side effects of drugs (for example, during chemotherapy), (c) poisoning, (d) damage after exposure to radiation, (e) burn scars, (f) grave internal diseases, (g) serious infections  and immunological disorders of the scalp, (h) hormone dysfunction, (i) nutrient deficiency, (j) genetic factors (hereditary in nature).

Alopecia areata:

This hair loss is round and usually a locally-restricted loss of hair which mostly affects the hair of the scalp. As possible cause of it is a disturbance in the immune system, wherein the cells of the hair follicle are wrongly identified as foreign body and are fought against. Alopecia areata may last long or may be present only for a short time only to disappear again all by itself without a trace.

20 % of patients report that another member of the family is also affected, thus the assumption that it is genetically caused.

In worst cases, it can come to a loss of all hair of the scalp (Alopecia totalis) or to a loss involving the whole body (Alopecia universalis). Nowadays, alopecia areata can often be treated well using an array of medicines.

Diffuse Alopecia:

When we talk about diffuse alopecia, we refer to the equally distributed loss of hair throughout the scalp. It occurs more often in women than in men. The causes can be hormone dysfunction, stress, iron deficiency, grave infections, side effects of drugs (Alopecia medicamentosa), diseases of the thyroid glands and poisoning (for example, thallium). After getting rid of the cause, hair loss usually comes to a stop.

For instance, cancer treatment with application of cytostatics (chemotherapy) is a common cause of this kind of hair loss.

Alopecia traumatica / Alopecia mechanica:

Alopecia traumatica occurs in scars resulting from an accident (for example, wound cutting through the eyebrows) or burns (causing irreversible destruction of the hair follicle).

Alopecia mechanica is caused by permanent exertion of physical force like pressure, rubbing, and pulling. The following examples can lead to this kind of alopecia: (a) constant carrying of heavy load on the head, (b) hair styles with tight knots and braids, (c) compulsive pulling of the hair, (d) long bedridden conditions, and (e) placing the head in one and the same position for long periods of time while lying down.

Androgenetic Alopecia (male pattern baldness):

The hereditary form of hair loss (= male pattern baldness) is by far the most frequent form worldwide. It primarily affects only the male. However, there are also rare cases, wherein the females are involved, too. In the latter case, though, they are usually affected in a much milder form. 

Androgenetische Alopezie
Androgenetic alopecia is omnipresent. One is less affected, one more….


A great majority of males would be in one way or the other confronted with this kind of hair loss in the course of their life. In case of a highly sensitive disposition, this may already manifest in the early years of puberty. The cause of this type of hair loss is the inherited or genetically-defined hypersensitivity of the hair follicles of the scalp to the hormone dihydrotestosterone (usually abbreviated as DHT). DHT is a by-product of metabolism of the male sex hormone. The transformation of testosterone into DHT takes place through the action of the enzyme 5-alpha-reductase. And there are 2 subtypes of this enzyme.

The DHT shortens the life cycle of the sensitive hair follicles. The number of hair in telogen phase increases. In the end, the formerly strong terminal hair is gradually converted into fine, tiny vellus hair. The result is no other than a presumably barren area to the naked eye, i.e., a balding head is in progress!


Testosteron metabolism through 5- alpha- reductase  

 Miniaturisierung der Haarfollikel durch DHT

Miniaturising of the hair follicles through DHT


The final cause of the male pattern baldness has not yet been 100% cleared. Probably, there are other factors aside from DHT, whose role are not yet well investigated.

With a few exceptions, hair baldness takes the following course of development:
At first, small areas of hair loss develop to the left and right side of the front hairline. This area increases afterwards resulting in the hairline's receding backwards. Thus baldness of the forehead area results. Oftentimes, a similar development simultaneously takes place around the tonsure ("vertex" - in the rear part of the head, where the hair whirl is located) resulting in the thinning of the hair. With time, the dimension of the areas grow and soon they join together forming a fully bald head, with a crown of hair still remaining at the back of the head and the temples. Depending on the genetic disposition and sensitivity, the end stage of hair loss could either be hair loss of the hairline or a full one. The development of baldness varies. Sometimes, some men retain their small baldness of the front hairline till old age without any trace of exacerbation. In rare cases, it is only a thinning of the hair at the tonsure area (without baldness of the sides of the hairline without any progression). The most prominent example for this type of hair loss is the formerly international soccer football player from France, Zinedine Zidane.

In order to describe the state and the possible development/stages of baldness, the internationally-acclaimed Norwood- Hamilton- scale was introduced. 7 phases are distinguished. Phase 1 meens no hair loss. Therefore phase one is usually not shown in the most drawings:


 Norwood- Hamilton- Skala

Norwood- Hamilton- Scale


Women can also be affected by androgenetic alopecia. Internationally, its stages are classified using the Ludwig scale:

 Ludwig- Skala

Ludwig scale