D

desensitization A therapeutic method in which
gradual exposure to an ALLERGEN builds up the
body’s tolerance for the allergen, diminishing the
IMMUNE RESPONSEto encountering it. IMMUNOGLOBU-
LINE (IgE) is primarily responsible for the symp-
toms associated with type I HYPERSENSITIVITY
REACTION(allergic reaction), initiating the release
of histamines, LEUKOTRIENES, and PROSTAGLANDINS.
These substances induce INFLAMMATION(swelling),
itching, sneezing, coughing, and other physiologic
responses that represent the body’s attempt to rid
itself of the offending substance. Desensitization
gradually activates an immunoglobulin G (IgG)
ANTIBODYthat binds, instead of IgE, with the aller-
gen. Because IgG does not activate mast cells, the
binding produces none of the symptoms that char-
acterize a type I hypersensitivity reaction.
In desensitization the allergist injects the per-
son with very small amounts of the allergen
(“allergy shots”) regularly over a period of three to
five years. Relief is generally apparent in about a
year. Approximately 80 percent of people who
have seasonal allergies respond to desensitization,
bringing their hypersensitivity reactions within
tolerable parameters or eliminating them entirely.
Desensitization, sometimes called allergy
IMMUNOTHERAPY, is also highly effective for allergies
to pet dander (especially cats), molds, and insect
stings. Desensitization may be a therapeutic option
for severe FOOD ALLERGIESthat are difficult to man-
age by avoiding the food.
Desensitization injections carry the risk for
instigating a severe hypersensitivity reaction
including ANAPHYLAXIS, though this is rare. Some
people experience temporary discomfort with the
shots. Most people who undergo desensitization
treatment have few side effects, however, and
find the long-term benefit of reduced hypersensi-

tivity reaction greatly improves their QUALITY OF

LIFE.

See also ALLERGIC ASTHMA; ALLERGIC CONJUNCTIVI-

TIS; ALLERGIC RHINITIS; ALLERGY; ALLERGY TESTING;

ASTHMA; COUGH; HISTAMINE; LIVING WITH ALLERGIES;

MAST CELL; SNEEZE.

disease-modifying antirheumatic drugs

(DMARDs) Medications that alter the IMMUNE

RESPONSEslow or stop the progression of certain

degenerative, AUTOIMMUNE DISORDERS. The most

common use of DMARDs is to treat RHEUMATOID

ARTHRITIS. DMARDs provide relief from symptoms

such as INFLAMMATIONand PAIN, and in many peo-

ple also reduce the JOINT deformities associated

with rheumatoid arthritis and other degenerative

conditions that result from the same disease

process (such as ANKYLOSING SPONDYLITIS).

DISEASE-MODIFYING

ANTIRHEUMATIC DRUGS (DMARDS)

anti-TUMOR NECROSIS FACTORS(TNFS) azathioprine

chloroquine cyclophosphamide

cyclosporine etanercept

gold salts hydroxychloroquine

infliximab leflunomide

methotrexate penicillamine

sulfasalazine

How These Medications Work

DMARDs work by altering or suppressing the

immune response. Some of the DMARDs are

immunosuppressive CHEMOTHERAPYdrugs (such as

methotrexate and cyclosporine), though

researchers do not fully understand how they

work to reduce autoimmune inflammation. Other

DMARDs are antimalarial medications that sup-

press immune function by blocking the action of

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