Summary

24.1 Allergic Response

• Allergic responses are inappropriate or exaggerated responses of the body’s immune system to a substance that is usually harmless. The body has multiple defense mechanisms that recognize and eliminate antigens, or foreign proteins that invade the body.
• Hypersensitivity is an abnormal heightened response to any type of stimulus; it does not normally occur after the initial exposure to an allergen.
• Type I hypersensitivity, or anaphylactic response, is facilitated by IgE antibodies produced by the immune system in response to allergens like dust mites, animal dander, and pollens.
• Type II, or cytotoxic-mediated, responses against cell surface and extracellular matrix proteins are facilitated by IgG and IgM antibodies.
• Type III, or immunocomplex, reactions are also facilitated by IgG and IgM antibodies that react with soluble antigens to create antigen-antibody complexes.
• Type IV, or delayed-type, hypersensitivity is a reaction where tissue damage is the result of T cell–dependent macrophage activation and inflammation.

24.2 Allergic Rhinitis

• The most common type of respiratory allergy is allergic rhinitis.
• The symptoms of allergic rhinitis are nasal congestion, sneezing, nose and throat itching, abundant amounts of serous nasal drainage, itching, watery eyes, hyposomnia, headache, and post-nasal drip.
• An allergic rhinitis diagnosis is dependent on the patient’s history, as well as a clinical examination and diagnostic test results.
• There are several options when it comes to managing allergic rhinitis.
• Avoidance therapy may be used to minimize an individual’s exposure to allergens and thereby decrease symptoms.
• Pharmacologic therapy is also used; medications include adrenergic agents, antihistamines, second-generation H1 receptor antagonists, mast cell stabilizers, corticosteroids, and leukotriene modifiers.
• Another option to treat or manage allergic rhinitis is immunotherapy, which includes subcutaneous immunotherapy (SIT), epicutaneous immunotherapy (EPIT), and sublingual immunotherapy (SLIT).

24.3 Types of Dermatitis

• Dermatitis, or inflammation of the skin, encompasses several types of skin conditions with the same inflammatory reaction pattern and manifestations.
• The three types of dermatitis related to allergic disorders are contact dermatitis, atopic dermatitis (eczema), and dermatitis medicamentosa (drug reactions).
• Contact dermatitis is a type IV delayed hypersensitivity that may be caused by extreme exposure to irritants like soaps, solvents, and detergents.
• Atopic dermatitis, also called atopic eczema, is a type I immediate hypersensitivity disorder. Atopic dermatitis may be caused by food allergens and environmental triggers.
• Dermatitis medicamentosa is a type I hypersensitivity disorder resulting from drug reactions.
• Dermatitis can be diagnosed by physical examination, exposure history, and patch testing (except for widespread reactions and drug reactions).
• Medical therapies and related care should be individualized and may include identification and removal of irritants, avoidance therapy, phototherapy, aluminum acetate, cool compresses, systemic corticosteroids, topical corticosteroids, oral antihistamines like diphenhydramine, hydrophilic creams, petrolatum, antibiotics, and nonsteroidal anti-inflammatory agents.
• Severely affected individuals may be prescribed immunosuppressants.
• Other measures include wearing cotton fabrics to decrease pruritus, bathing and washing with mild detergents, moisturizing after bathing, maintaining the room temperature from 68°F to 72°F (20°C to 22.2°C), using humidifiers in winter, and avoiding irritants, animals, dusts, sprays, and perfumes.

24.4 Urticaria and Angioneurotic Edema

• Urticaria is a type I hypersensitivity allergic reaction involving the skin.
• Angioneurotic edema is a condition that is depicted by urticaria and dispersed swelling of the deeper skin layers.
• Urticaria may appear anywhere on the body, while angioedema typically occurs on the face, hands, feet, or throat.
• These conditions often occur together but can appear without the presence of the other.
• These conditions may be the result of exposures to allergens like food, medications, insect stings, physical stimuli, latex, blood transfusions, bacterial or viral infections, pet dander, plants, and pollen.
• Urticaria is characterized by edematous red or pink wheals that vary in size from 2–4 mm. Pruritus and angioedema may also be present with this disorder.
• The assessment should include vital signs as well as a review of the systems to identify potential causes or a severe case.
• Interventions may be aimed at improving symptoms, administering medications, educating the patient about avoidance therapy, avoiding aggravating factors, and promoting home-based care. Nursing interventions for improving symptoms may include administering medications and eliminating identified or suspected triggers. Medications may include antihistamines and system corticosteroids.
• Angioedema involves swelling of the deeper skin layers; it most commonly occurs in the face (eyelids, lips, tongue, cheeks), hands, feet, genitalia, or throat.
• Angioedema can also occur in mucous membranes of the gastrointestinal tract, bronchi, and larynx.
• Angioedema is either histamine-mediated or bradykinin-mediated and is characterized by non-pitting swelling of the dermis and subcutaneous layers.
• Interventions may be aimed at improving symptoms, administering medications, educating the patient about avoidance therapy, and promoting home-based care. Medications may include epinephrine in extreme cases or those causing difficulty breathing. Most cases resolve on their own within two to four days. Antihistamines or corticosteroids may also be prescribed.

24.5 Allergy to Food

• Food allergies are IgE-mediated type I hypersensitivity reactions.
• The most common foods known to cause food allergies are peanuts, tree nuts, seafood, chocolate, berries, eggs, wheat, and milk.
• Reactions may include smooth muscle contraction, bronchial constriction, mucus airway secretions, wheal-and-flare skin reactions, increased capillary permeability, and vasodilation.
• Symptoms of food allergies range from mild to life-threatening and include a variety of allergy and gastrointestinal problems.
• All patients with food allergies should have an EpiPen and a medical alert bracelet.

24.6 Allergy to Latex

• Latex is a natural rubber protein derived from the sap of the rubber tree.
• There are various types of reactions to latex, including irritant contact dermatitis, allergic contact dermatitis, and latex allergy, which is a type I IgE-mediated immediate hypersensitivity due to the natural rubber proteins.
• Latex allergies can cause a variety of reactions including erythema; edema; burning; pruritus; dry, thickened, and cracked skin; blisters; skin lesions; urticaria; rhinitis; flushing; laryngeal edema; bronchospasm; conjunctivitis; asthma; angioedema; extreme vasodilation; anaphylaxis; cardiovascular collapse; and even death.
• Those in settings where patients have a risk of exposure should assess the patient for latex allergies and may use a screening tool to aid in identifying if there is a risk. If there is a risk, the nurse should identify latex-free alternatives.
• Other interventions may be aimed at improving symptoms caused by reactions and educating at-risk individuals about avoidance therapy, emergency measures, and foods reported to be cross-linked with latex allergies.
• Primary management is avoiding exposure.
• Patients with latex allergy should have a medical alert bracelet and a kit containing antihistamines and EpiPen.
• The patient should also report this allergy to emergency services and health care facilities and may be advised to put a warning label on their vehicle.
• Patients may also need to seek new employment or be referred to support groups.

24.7 Anaphylaxis

• Anaphylaxis is a potentially life-threatening, type I hypersensitivity response resulting from the rapid release of IgE-mediated chemicals in an attempt to eliminate a triggering allergen.
• Anaphylaxis generally occurs withing minutes to hours of exposure and involves the integumentary, respiratory, cardiovascular, and gastrointestinal systems.
• Common causes of anaphylaxis include foods, insect stings, latex, medications, and other pharmaceutical agents like serums or skin-testing antigens.
• Clinical manifestations include bronchoconstriction, increased vascular permeability, flushing, angioedema, urticaria, mucosal inflammation and edema, and hypotension.
• Anaphylaxis reactions include multiple organ systems at once and may range from mild to moderate to severe.
• Mild reactions include peripheral tingling, warm sensations, and a sense of fullness in the throat and mouth. Periorbital swelling, sneezing, nasal congestion, pruritus, and tearing from the eyes may also occur.
• Moderate reactions include any of the mild symptoms, with the addition of anxiety and flushing. Some moderate reactions may be more severe and include edema of the airways or larynx, dyspnea, wheezing, cough, and bronchospasm.
• Severe reactions are referred to as anaphylactic shock. They have a quick onset and include any symptoms from the mild or moderate categories. Those symptoms rapidly progress to bronchospasm, severe dyspnea, edema of the larynx, cyanosis, and hypotension. Other symptoms like dysphagia, seizures, abdominal cramping, vomiting, and diarrhea may also occur.
• Assessment for anaphylaxis should include airway, breathing, circulation, level of consciousness, and exposure of the skin.
• When it comes to anaphylaxis reactions in an acute care setting, the nurse must assess the patient for any signs and symptoms of anaphylaxis in order to quickly intervene. The nurse should assess airway, breathing, vital signs, signs of increasing edema, and respiratory distress.
• Interventions include intubation, emergency medication administration, intravenous line insertion, fluid administration, and oxygen administration. CPR may be warranted in the event of cardiac arrest. Antihistamines and corticosteroids may also be given in adjunction with epinephrine.
• Patients who have experienced anaphylaxis and received epinephrine should be taken to an emergency room, if not already present in a hospital setting, as they should be monitored for rebound or delayed reactions.