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When there are patches of scalp or other parts of the body that are completely
hairless, it is generally a case of alopecia areata. It is a non-scarring, inflammatory
disease in which there is complete hair loss. Alopecia areata may affect men,
women and children alike. Although this is not a life threatening disease, alopecia
areata often has severe psychological and sociological implications, as at times
the condition can result in complete hair loss and cause disfigurement.
 The Hair Follicle Cycling
There are usually three stages in hair follicle growth in mammals – anagen,
catagen and telogen. Anagen is the period of active growth. This is followed
by a period of apoptosis or regression. Finally there is telogen or a period
of rest before the next phase of anagen begins. In this phase generally the
hair fiber is shed.
Causes of Alopecia Areata
When the anagen hair follicles are damaged, it may result in alopecia areata.
It has been observed that anagen hair follicles sometimes enter the telogen
state prematurely, causing alopecia. When this condition occurs repeatedly,
poor aberrant hair fibers are produced from dystrophic anagen follicles. Scientists
have two views on the state of the hair follicles in alopecia areata. Some
believe that the hair follicles transit rapidly between dystrophic anagen
and telogen stages while another school of thought believes that they are
arrested in a state of telogen.
Thus in early alopecia areata, the disruption of the normal hair follicle
cycling results in a disproportionate ratio of anagen, catagen and telogen
hair follicles resulting in clusters of telogen hair falling off from the
scalp and other parts of the body. The hair shafts that fall off appear to
have roots that indicate telogen hair follicles. At the periphery of the bald
patch are found fractured hairs with sharp pointed tips. They are called exclamation
mark hairs because they resemble exclamation marks.
Types of Alopecia Areata
On clinical examination, alopecia areata appears as a smooth bald patch,
which at times may further expand in size. Similar bald patches may appear
subsequently in other areas. Alopecia areata has been classified into different
types according to the severity of the disease and its various forms.
- Alopecia Totalis: In this the scalp is affected and all the hair from
the scalp is lost resulting in a smooth bald head.
- Alopecia Universalis:
This is a severe form of alopecia where there is loss of all body and
scalp hair including eyebrows, eyelashes, underarms
and
pubic hair.
- Alopecia Areata Barbae: When alopecia affects the hair
of the beard region, it is known as alopecia areata barbae.
- Reticulated
Areata Barbae: In this form of disease, bald patches may not be found
but there is hair loss in irregular patterns in a
net like fashion.
In the scalp, there are regions of hair loss interspersed with areas
with normal hair growth. When affected with reticulated alopecia,
patients may
have hair falling from one region but new hair growth in another
region. This phenomenon may for many months or years.
- Ophiasis type of
alopecia areata shows a band like hair loss. It occurs mostly in the temporal
or the occipital regions of the
scalp
and is therefore
more difficult to treat, as most medicines have a delayed action
on these areas. Ophiasis type of alopecia is identified by a turban
or
snake like pattern
on the periphery of the scalp. Ophiasis in Greek means serpent
and this is how the disease gets its name.
- Diffusion Type of Alopecia
Areata: In this case, there is a premature cessation of anagen growth,
which causes partial hair
loss throughout
the scalp. No distinct patches are evident. It may not be possible
to identify
the disease clinically, as it can be mistaken for telogen hair
loss,
which is diffused hair loss caused by stress, certain physical
conditions like puberty
or childbirth, chronic illness, or trauma. It is also similar
to anagen effluvium, which is hair loss in the anagen stage
due to
chemotherapy
or radiation treatment. In some cases of hair loss on top of
the head, it also resembles typical male or female pattern of hair loss
or even trichotillo where people pull
out their own hair. A biopsy is perhaps the best way to diagnose the disease
specifically. Dermatologists also look for the exclamation type of broken
hairs as indication of alopecia areata.
- Perinevoid Alopecia Areata: This
is a relatively unusual type of alopecia areata where spots of skin are
found having properties different from the
surrounding general skin area. Around these pigmented spots or nevi are
found patches having characteristics of alopecia areata.
Ikeda
Classification of Alopecia Aerata Types
Ikeda has broadly classified alopecia areata into type I, type II, type III
and type IV categories under which each of the above forms of alopecia areata
can be categorized. The Ikeda type of classification is as follows:
- Type I – This consists of 80% of alopecia areata cases. People with
type I alopecia areata had round bald patches with no previous family
history of the disorder. They usually did not suffer from additional conditions
like
hypertension or endocrinal disorders.
- Type II – Individuals with
type II alopecia areata usually carried a history of asthma, allergic
rhinitis or dermatitis. The alopecia is generally
seasonal and causes a longer period of hair loss. The hair loss pattern
is usually ophiasis, reticular or round. The patch may even have an intermediate
shape. 75% of such patients finally ended up with alopecia totalis.
- Type
III – This form of alopecia areata has a frequency of 4%. Patients
with type III alopecia areata have chronic disease activity and a history
of parental hypertension. The alopecia is of a reticular pattern and 39%
of the patients usually develop alopecia totalis.
- Type IV form of alopecia
areata usually develops in people over 40 years
of age. They have a round, reticular or ophiasis pattern of alopecia, which
usually remains for a prolonged period of time, finally leading to alopecia
totalis in 10% of the group.
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Alopecia
Areata 
Alopecia
areata overview