Clinical Manifestations of Type I Hypersensitivity Flashcards
The prevalence of allergic diseases has increased greatly in developed countries in the last __ years, and it is estimated that __% of the world’s population has allergic sensitization to common environmental antigens such as pollen or peanuts
50; 40; pollen or peanuts
fifth leading cause of chronic disease in all age-groups as well as the third leading cause of chronic disease in children
allergies
clinical manifestations caused by release of inflammatory mediators from mast cells and basophils vary from a localized skin reaction to a severe systemic response
anaphylaxis
If an allergen is inhaled, it is most likely to cause respiratory symptoms such as
asthma or rhinitis
Ingestion of an allergen may result in ___________ _________, whereas injection into the bloodstream can trigger a systemic response
gastrointestinal symptoms
most common form of atopy, or allergy; it
affects between 10% and 30% of populations worldwide. Symptoms include paroxysmal sneezing; rhinorrhea, or runny nose; nasal congestion; and itching of the nose and eyes
Rhinitis
Although the condition itself is merely annoying, complications such as
sinusitis,
otitis media (ear infection),
eustachian
tube dysfunction, and
sleep disturbances may result
examples of airborne foreign particles that act
directly on the mast cells in the conjunctiva and respiratory mucous membranes to trigger rhinitis
Pollen,
mold spores,
animal dander, and
particulate matter from house dust mites
Seasonal allergic rhinitis, triggered by tree and grass pollens in the air during the spring in temperate climates, is called
“hay fever”
*Greek word for “panting” or “breathlessness,” is caused by inhalation of small particles such as pollen, dust, or fumes that reach the lower respiratory tract.
*It can be defined clinically as recurrent airflow obstruction that leads to intermittent sneezing, breathlessness, and, occasionally, a cough with sputum production.
Asthma
caused by bronchial smooth muscle contraction, mucosal edema, and heavy mucus secretion
airflow obstruction
most common food allergies are caused by
cow’s milk,
eggs,
nuts,
soy,
wheat,
fish, and shellfish
Symptoms limited to the gastrointestinal
tract include
whereas spread of antigen through the bloodstream may cause ____ and ____on the skin, asthma, rhinitis, or anaphylaxis
cramping, vomiting, and diarrhea;
hives and angioedema
manifest as either acute urticaria or eczema
Local inflammation of the skin, or dermatitis
appear within minutes after exposure to the
allergen and are characterized by severe itching, erythema (redness) caused by local vasodilation, leakage of fluid into the surrounding area, and a spreading area of redness around the center of the lesion
Urticaria, or hives
Commonly called a whealand-flare reaction, this reaction is caused by release of vasoactive mediators from mast cells in the skin following contact with allergens such as pet dander or insect venom. When these reactions occur deeper in the dermal tissues, they are known
as
angioedema
Urticaria can also appear as a result of other clinical manifestations such as
anaphylaxis and food allergies
*can take on a variety of forms, from erythematous, oozing vesicles to thickened, scaly skin, depending on the stage of activity and age of the individual
*it is a chronic, itchy skin rash that usually develops during infancy, persists during childhood, and is strongly associated with
allergic rhinitis and asthma
Atopic eczema
most severe type of allergic response because it is an acute reaction that simultaneously involves multiple organs. It may be fatal if not treated promptly
Anaphylaxis
Coined by biologists ___ ___ and ___ ____ in 1902, the term literally means “without protection.”
Paul Portier and Charles Richet
Anaphylactic reactions are typically triggered by
glycoproteins or large polypeptides
Smaller molecules, such as ______, can trigger anaphylaxis by acting as haptens that may become immunogenic by combining with host cells or proteins
penicillin
Typical agents that induce anaphylaxis include ____ from bees, wasps, and hornets; _____ such as penicillin; and ____ such as shellfish, peanuts, and dairy products
venom; drugs; foods
Clinical signs of anaphylaxis begin within _____ after antigenic challenge and may include bronchospasm and laryngeal edema, vascular congestion, skin manifestations such as urticaria (hives) and angioedema, diarrhea
or vomiting, and intractable shock because of the effect on blood vessels and smooth muscle of the circulatory system
minutes
_____ may result from asphyxiation because of upper-airway edema and congestion, irreversible shock, or a combination of these symptoms
Death
multiple exposures result in additional accumulation of IgE on the surface of the
mast cells and basophils
ignificant problem since the late 1980s after implementation of Universal Precautions by the
Centers for Disease Control and Prevention and Occupational Safety and Health regulations requiring health-care workers to wear gloves when performing laboratory procedures and working with patients
Latex sensitivity
Reactions to antigens in natural rubber latex include type__ hypersensitivity and contact dermatitis caused by skin irritation or type __ hypersensitivity
I ; IV
Type I hypersensitivity reactions include
urticaria,
rhinoconjunctivitis,
asthma,
angioedema, and
anaphylaxis
Sensitization to latex can occur as a result of direct skin contact or ______ __ _____ latex particles released when gloves are donned and removed.
The risk of the latter occurring is increased when ______ _____ is used in gloves because residual latex proteins can bind to the powder particles.
inhalation of airborne; cornstarch powder
Groups at particular risk for latex allergy include
health-care workers;
rubber industry workers;
patients who have had multiple surgeries, such as children with spina bifida; and
atopic individuals, particularly those who are allergic to certain foods that cross-react with latex allergens.
These policies may include use of low-protein, powder-free gloves or gloves made from non-latex materials such as
nitrile,
neoprene,
vinyl, or synthetic polyisoprene rubber
