Page 212 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 7-1 Integumentary System

ALOPECIA AREATA

Alopecia areata is an autoimmune disease that causes
discrete circular or oval areas of nonscarring alopecia.
This form of alopecia has several clinical variants,
including alopecia totalis, alopecia universalis, and an Alopecia areata approaching the
ophiasis pattern. Therapy is often difficult. The disease alopecia totalis stage. This patient
can have profound psychological impact, especially in has lost almost all of her scalp hair.
young patients. It is critical to address this issue, because
the effects on the patient’s psychological well-being are
often more severe than the actual hair loss.
Clinical Findings: Alopecia areata can affect indi-
viduals of any age but is most frequently seen in chil-
dren and young adults. It is estimated to affect 1% of
the population. Both sexes are equally affected, and
there is no race predilection. The first sign is hair loss
in one specific area of the scalp. The hairs fall out in
large numbers, especially when pulled. The patches of
hair loss typically have an oval or circular pattern.
There may be one or more than a dozen areas of
involvement. The scalp hair is the most commonly
affected region. The affected scalp is smooth without
evidence of scarring or follicular dropout. Small, stubby
hairs may be present at follicular openings and have
been termed “exclamation point hairs.” All hair regions
may be involved, including the eyebrows, eyelashes, and
beard.
Alopecia areata has an unpredictable, waxing and
waning course. Areas may begin to grow back as new
patches form. It is not uncommon for a patient to have
one solitary episode with spontaneous resolution and
no future episodes. Some patients develop patches of
alopecia intermittently over their lifetime. Complete
loss of the scalp hair caused by alopecia areata is termed
alopecia totalis. The rarest variant is alopecia universalis,
which causes loss of all hair in all locations. These two
forms of alopecia areata are very difficult to treat.
Patients with both alopecia totalis and alopecia univer- Alopecia areata with the characteristic
salis need psychological assessment, because the loss of oval and circular areas of nonscarring
hair has severe social and self-esteem consequences. alopecia
Patients often benefit from consultation with a profes-
sional psychologist or psychiatrist. Alopecia areata
support groups can be extremely helpful.
The ophiasis pattern of alopecia areata is less com-
monly seen. It involves the parietal scalp dorsally to the
occiput bilaterally. The diagnosis is typically made on
clinical grounds. A skin biopsy is rarely needed. The
hair pull test is a diagnostic test that can be performed
at the bedside. It is positive when more than three hairs
are pulled out in and around the patch of alopecia
areata. If the hair is actively shedding, this test should
be performed only once, because the number of hairs
removed is large and can be very upsetting to the
patient. The hair that regrows is often lacking in
pigment and appears white or gray. Over time, these
white hairs are replaced with pigmented hairs as the
hair pigmentation machinery begins to work again.
Histology: Skin biopsies of the scalp of an affected
area show a dense lymphocytic infiltrate surrounding such as autoimmune thyroid disease. It is believed to be issues and should be offered therapy. However, no
all the hair bulbs in what has been termed a “swarm of polygenic in nature. therapy has been shown to be uniformly effective, and
bees” pattern. There are increased numbers of catagen Treatment: Treatment consists of proper assessment most have only anecdotal reports of efficacy. Topical
and telogen hairs. The epidermis is normal. of the patient and how the disease is affecting the retinoids and corticosteroids are used, as well as intra-
Pathogenesis: Alopecia areata is believed to be an patient’s life in general. Some individuals tolerate the lesional steroid injections if the areas are small enough.
autoimmune inflammatory disease of T cells that, for condition without adverse psychological effects; for Contact sensitization with squaric acid has had equivo-
unknown reasons, attacks certain hair follicles. It may them, the best treatment is a watch-and-wait approach. cal results. Oral steroids should be avoided, because the
be seen in association with other autoimmune diseases Others with mild disease may have severe self-esteem long-term side effects do not warrant their use.

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