Week 8 - Chpt.33 - Allergy Disorders

IMMUNOLOGIC DEFINITIONS

  • Allergen – substance that causes manifestations of allergy

  • Allergy – an exaggerated/inappropriate immune response to substances that are normally harmless

  • Antigen – substance that the body identifies as a foreign invader, induces production of antibodies

  • Antibody – protein substance developed by B cells in response a specific antigen

  • Histamine – substance in the body that causes increases gastric secretion, dilation of capillaries, & constriction of the bronchial smooth muscle

    • feeling flushed due to dilated capillaries

  • ingest → ate something

  • inhale → breathed something in

  • injected → some type of bite that goes into your blood stream

  • absorbed → something that touched your skin that gets absorbed into the body

  • cytotoxic infusion → like chemotherapy or a hemolytic transfusion

  • if a patient has never had a medication before it is best to monitor closely incase of an allergy reaction

  • people allergic to shellfish or kiwi have increased risk of allergy to radiocontrast dye

  • always be mindful of latex allergy

ANAPHYLAXIS & ANAPHYLACTOID REACTIONS

Clinical Manifestations – based on severity

  • Mild – within two hours of exposure

  • Peripheral tingling, warm sensation, feeling of fullness in mouth/throat, nasal congestion, periorbital swelling, pruritis, sneezing, eye tearing

  • Moderate - within two hours of exposure

    • Flushing, warmth, anxiety, pruritis, edema of airway/larynx, bronchospasm, dyspnea, cough, wheezing, & same as mild

  • Severe – within seconds, minutes & hour

    • Same as mild/moderate with rapid progression to bronchospasm, laryngeal edema/dysphagia, dyspnea, cyanosis, hypotension, abdominal cramping, vomiting, diarrhea, seizure

    • Cardiac arrest or comatose state may follow these symptoms

    • patients may not recover can die or body will go into a comatose state & shut down

ANAPHYLAXIS & ANAPHYLACTOID REACTIONS: Prevention

  • Avoidance of potential allergens

    • Ie: insect bites, snakes/spiders, food items

  • Screen patients for allergies before prescribing, prior to first dose

    • Assess whether patient has had previous anaphylactic, or mild reactions to medications/dyes in past

  • Clients with anaphylactic history should wear medical bracelet

  • Administer Epinephrine as soon as possible → often done on the thigh

  • Desensitization therapy for patients that are allergic to medications that are medically necessary

    • Ie: patients with diabetes & insulin allergy, patient allergic to PCN

ANAPHYLAXIS & ANAPHYLACTOID REACTIONS: Treatment

  • Medical management – depends on severity

    • Epinephrine administered 1:1000 dilution – subQ, may be followed by IV admin

      • Epi 1:1000 is SPECIFIC for allergic reactions

    • Cardiac arrest → Cardiopulmonary resuscitation (CPR)

    • Cyanosis/dyspnea → airway management, oxygen administration

    • Manage inflammatory response → Antihistamines and corticosteroids

    • Hypotension → IV fluids (crystalloid/colloid),

  • Nursing

    • Assess ABC, notify rapid response team

    • Emergency measures – prepare patient for intubation, admin rescue medications for cardiac/pulmonary support/epi, initiate IV access & instill fluids

    • Provide patient education about prevention, self admin of epi

URTICARIA (HIVES)

Type I Hypersensitivity reaction characterized by sudden presentation of

pruritic pink/red papules that process to wheals of varying sizes

  • Acute urticaria – evolves over minutes/hours, resolves within 24 hours

  • Commonly caused by:

    • Infections, allergic reactions to food/insect bites/medications

  • Diagnosed by:

    • Health history, physical exam

  • Treatment:

    • Eliminate causative agent

    • Administer antihistamines (cetirizine (zertec), fexofenadine (allegra), loratadine (claritin))

    • Minimize conditions that can worsen urticaria ie: heat, stress, alcohol, tight clothes

ANGIOEDEMA (MAST-CELL MEDIATED)

Allergic reaction characterized by fluid accumulation within subcutaneous

and mucous membrane’s; often occurs with urticaria and can be life-

threatening when paired with anaphylaxis sxs.

  • Caused by: allergy to foods/latex/medications/insect bites

  • Clinical manifestation

    • Can occur within seconds, minutes, or slowly over 1-2 hours; resolves within 24-48 hours

    • Nonpruritic (get really puffy face), brawny, wide-spread, nonpitting edema that presents on the lips, eyelids, cheeks, hands, feet, genitalia, tongue

    • Mucous membranes of the larynx, bronchi, and GI tract can also be affected

  • Diagnosed by: health history, physical exam

  • Treatment:

    • Eliminate causative agent

    • Administer antihistamines (cetirizine, fexofenadine, loratadine)

    • If anaphylaxis is present: IM epinephrine

  • these patients should still go to a hospital incase anaphylaxis takes place

    • because angioedema & urticaria can be precursors to anaphylaxis