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 ophiasis pattern. Therapy is often difficult. The disease can have profound psychological impact, especially in 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 individuals of any age but is most frequently
seen in children 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 universalis need psychological
assessment, because the loss of hair has severe social and self-esteem
consequences. Patients often benefit from consultation with a professional
psychologist or psychiatrist. Alopecia areata support groups can be extremely
helpful.
The ophiasis
pattern of alopecia areata is less commonly 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 all the hair bulbs in what has been termed a “swarm of bees”
pattern. There are increased numbers of catagen and telogen hairs. The
epidermis is normal.
Pathogenesis: Alopecia areata is
believed to be an autoimmune inflammatory disease of T cells that, for unknown
reasons, attacks certain hair follicles. It may be seen in association with
other autoimmune diseases such
as autoimmune thyroid disease. It is believed to be polygenic in nature.
Treatment:
Treatment
consists of proper assessment of the patient and how the disease is affecting
the patient’s life in general. Some individuals tolerate the condition without
adverse psychological effects; for them, the best treatment is a watch-and-wait
approach. Others with mild disease may have severe self-esteem issues and should be
offered therapy. However, no therapy has been shown to be uniformly effective,
and most have only anecdotal reports of efficacy. Topical retinoids and
corticosteroids are used, as well as intralesional steroid injections if the
areas are small enough. Contact sensitization with squaric acid has had
equivocal results. Oral steroids should be avoided, because the long-term side effects
do not warrant their use.
