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Types
of alopecia areata
Alopecia areata refers to a non-scarring, inflammatory, hair
loss disease that is seen in men, women and children. This condition
most commonly manifests itself as patchy areas of hair loss. Alopecia
areata most frequently occurs on the scalp, but any hair-bearing
region of skin on the body can be affected. In severe cases, alopecia
areata can even progress to complete loss of all body hair, a
condition called alopecia universalis. While not a life threatening
condition, Alopecia areata is nevertheless serious because of
the psychologically and sociologically devastating effects of
the condition on the victim.
Though alopecia areata can occur in many different forms, all
the presentations are caused by the same basic disease mechanism.
Normally, hair growth in each hair follicle occurs in a cycle.
There are three main phases of the hair growth cycle; anagen,
catagen, and telogen. Anagen is the active growth phase when hair
fiber is produced. This is followed by catagen, a period of controlled
regression of the hair follicle. Ultimately the hair follicle
enters telogen where it is in a so-called resting state.
Alopecia areata results from selective, usually reversible damage
to anagen hair follicles. Studies indicate that the initial event
in the development of alopecia areata is the premature precipitation
of anagen follicles into the telogen, resting state of the hair
follicle cycle. Most commonly, hair follicles exit anagen, enter
catagen, and then shed the hair fiber upon entering telogen. In
alopecia areata the follicles may then try to proceed back into
the next anagen growth phase but, as a result of the continued
activity of the disease, produce poor aberrant hair fiber. Such
follicles are described as being in a dystrophic anagen state.
Some researchers believe the hair follicles continue indefinitely
to oscillate between several rapid cycles of dystrophic anagen
and telogen states. Others believe many of the follicles are eventually
arrested in telogen.
Clinically, Alopecia areata results in smooth, round or oval
bald areas. As the disease progresses, the first one or two patches
may expand in size and/ or other patches of hair loss may subsequently
develop. Based on the severity of disease and pattern of hair
loss, Alopecia areata can present with many different patterns
and can be classified as:
-
Alopecia totalis where all the hair on the scalp is lost, and
the surface of the scalp becomes totally smooth.
- Alopecia
universalis where there is loss of all hair on the head and
body, including eyelashes, eyebrows, underarm hair, and
pubic hair. This is considered to be the most severe form of alopecia
areata.
- Alopecia Areata Barbae is the term for an Alopecia
Areata lesion found in the region of beard hair.
- Reticulated
type of alopecia areata which differs from the more common patchy
loss, and is characterized by a net-like pattern
of hair loss in which irregular areas without hair are interspersed
with areas of hair on the scalp. Patients with the reticular
variant of patchy alopecia areata experience loss of hair in one site
concurrent with spontaneous hair re-growth in another area
of hair loss. This type of activity may go on for months to years.
- Some victims
of alopecia areata experience Ophiasis alopeci. This is a band-like
pattern of hair loss affecting the temporal
and occipital regions of the scalp. The bald area runs from ear to
ear at the back of the scalp. Ophiasis comes from the Greek
word serpent, and the pattern of hair loss covers the periphery of
the scalp like a serpent forming a turban over the edges of
the scalp. This type of hair loss is more difficult to treat compared
to most other forms of alopecia areata.
- Diffuse alopecia areata
has been attributed to a short anagen phase and subsequent inability
of hair to grow resulting in
a form of incomplete hair loss affecting the whole scalp without
distinct patches. This type can be difficult to diagnose and
may require a biopsy as the presentation may mimic a severe telogen
effluvium (diffuse hair loss caused by an interruption in
the normal hair growth cycle, often the result of trauma, such as
chemotherapy, childbirth, puberty, major surgery, severe stress,
and severe chronic illness). Long term diffuse alopecia areata
usually progresses to a mixture of bald patches and diffuse
hair loss which allows its distinction from chronic telogen effluvium
where completely bald areas do not develop.
- Perinevoid alopecia
areata is an unusual variant of alopecia areata and is characterized
by alopecia areata-like lesions developing
around pigmented nevi. Pigmented nevi are spots of skin with
color different from surrounding skin – usually moles.
Subterms
for alopecia areata
ALOPECIA AREATA (AA) - The most commonly used term and
covers all forms of the disease.
ALOPECIA PARTIALIS - The name given to specify patchy hair
loss. Not often used as "alopecia areata" suffices
ALOPECIA TOTALIS (AT) - The name given to specify alopecia
areata where all scalp hair is lost, but other body hair remains.
ALOPECIA UNIVERSALIS (AU) - The name given to specify alopecia
areata where all scalp and body hair is lost.
ALOPECIA AREATA BARBAE - The term for an alopecia areata
lesion found in the region of beard hair.
ALOPECIA AREATA OPHIASIS - The term used for an alopecia
areata lesion limited to extension along the scalp margin (Occipital
and temporal region - the strip of hair running from one ear around
the back of the head to the other ear). Ophiasis comes from the
latin "snake" due to the winding, snaking pattern the hair loss
has over the back of the head. The term was originally used by Cornelius
Celsus in 30AD
ALOPECIA AREATA DIFFUSA - A term occasionally used for an
alopecia areata lesion of general thinning of hair on the scalp.
It is usually simply called diffuse alopecia areata
RETICULAR ALOPECIA AREATA - The term used for the presence
of numerous small, well defined patches of hair loss
SISAIPHO ALOPECIA AREATA - This is a new term so far only
used by one clinical group in Seville, Spain (Munoz 1996). It is
defined as entire loss of scalp hair except for a narrow ring of
hair around the periphery.
TRIANGULAR ALOPECIA AREATA - A very rare form of alopecia
areata where the hair loss lesion presents in a triangular shape
PERINAEVOID ALOPECIA AREATA - A very rare form of alopecia
areata where hair is lost around nevi (moles or other skin growths)
Synonyms
for alopecia areata
These synonyms have largely fallen out of use:
- AREA CELSI
- ALOPECIA CELSI
- ALOPECIA CIRCUMSCRIPTA
- JONSTON'S ALOPECIA
- AREA JONSTONII
- PORRIGO DECALVANS
- TINEA DECALVANS
- CAZENAVE'S VITILIGO
- CELSUS' VITILIGO
- VITILIGO CAPITIS
NB Because of the arguments spanning several decades on the definition
of alopecia areata some of the older terms have been used interchangeably
with terms for other hair loss diseases. This is partly the reason
why new terms have superseded older, potentially confusing, names
for alopecia areata.
French
synonyms for alopecia areata
The French never accepted the term alopecia areata and often use
the term PELADE and sometimes TEIGNE PELADE, PELADE ACHROMATEUSE
and PELADE DECALVANTE.
German
synonyms for alopecia areata
Germans and German speaking populations typically use "alopecia
areata" and its various subterms. Occasionally however, the German
term KREISRUNDER HAARRAUSFALL is used which literally translates
as "circle-round hair-outfall".
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