Allergy and Immunology Quiz

Allergy Treatment

• Allergies are hypersensitivity reactions by the immune system, affecting approximately 40-50 million people in the United States
• Seasonal allergic rhinitis, an allergy to seasonal pollens, affects up to 20% of the US population
• Allergic reactions occur when the immune system treats an allergen as an invader, producing antibodies (IgE)
• These antibodies attach to mast cells, which contain histamine
• Histamine release triggers symptoms like wheezing, rash, runny nose, and itching
• Symptoms of allergies can be localized or generalized
• Allergic shiners are dark circles under the eyes caused by increased blood flow near the sinuses
• Allergic salute is a crease across the bridge of the nose due to persistent upward rubbing of the nose

Allergy Symptoms

• Dermal Symptoms:
  • Wheal (hives)
  • Rash
  • Redness
  • Urticaria (hives)
• Respiratory Symptoms:
  • Itchy eyes, nose, and throat
  • Runny nose
  • Stuffy nose
  • Sneezing
  • Coughing
  • Watery eyes
  • Conjunctivitis

Urticaria (Hives)

• Urticaria symptoms include itching, angioedema, redness, swelling, and wheals (blister-like vesicles)
• Urticaria can be triggered by insect bites, drugs, food allergies, or injections of allergen extracts (e.g., allergy shots)
• Urticaria is usually self-limiting

Urticaria Treatment

• Most urticaria cases are self-limiting
• Severe urticaria is treated with antihistamines and glucocorticosteroids

Allergic Rhinitis

• Allergic rhinitis symptoms include nasal itching, runny nose, nasal congestion, and sneezing
• Allergic Rhinitis is caused by inflammation and swelling in nasal passages
• Allergic rhinitis can be perennial or seasonal
• Symptoms often appear after a period of absence from allergen exposure
• Allergic rhinitis recurs seasonally due to the presence of memory CD4+ T cells, resulting in the production of allergen-specific antibodies (e.g., to tree, grass, or pollen)
• Allergic rhinitis is usually self-limiting

Allergic Conjunctivitis

• Allergic conjunctivitis symptoms include red, watery, itchy, or burning eyes, ocular puffiness, and stringy discharge
• It typically worsens during allergy and hay fever season
• Allergic conjunctivitis is typically self-limiting, however, decongestants, may cause, medicmentosa- rebound redness and nasal congestion

Occupational Allergies

• Latex proteins from disposable gloves, IV tubing and similar medical supplies may trigger occupational allergies
• Occupational allergens can become airborne and be inhaled, leading to dermal or respiratory symptoms

Drugs Used in Allergy Treatment

• Antihistamines (H1 Receptor Antagonists)
  • First generation: Diphenhydramine, chlorpheniramine, hydroxyzine, brompheniramine
  • Second generation: Cetirizine, levocetirizine, loratadine, desloratadine, fexofenadine
• Inhaled corticosteroids
• Mast cell stabilizers
• Leukotriene receptor agonists
• Vasoconstrictors

H1 Receptor Antagonist MOA

• Prevents histamine binding to H1 receptor sites, as drugs compete with free histamine for binding
• Half-life can vary, ranging from short (4-6 hours) to long (24 hours)
• Hydroxyzine metabolizes into Cetirizine

H1 Receptor Antagonist Adverse Effects

• Decreased alertness
• Sedation (most commonly with diphenhydramine and promethazine)
• Dizziness
• Dry mouth
• Blurred vision
• Urinary retention

Precautions for Antihistamines

• Use with caution in men with prostate disease and breastfeeding women
• Not recommended for children under 2 years

H1 Receptor Antagonist Warning Labels

• May cause drowsiness; alcohol may increase this effect (particularly in Ethylenediamines, alkylamines and piperazines)
• Swallow whole; do not crush or chew (extended-release products)
• May cause dizziness or drowsiness

Additional H1 Receptor Antagonist Warning Labels

• Protect from moisture; leave in foil packet until ready to use (disintegrating tablets).
• Dissolve reditab under the tongue (disintegrating tablets)
• Avoid orange, grapefruit, and apple juice (fexofenadine)
• Prime inhalers before use

Look-Alike/Sound-Alike Drugs

• Diphenhydramine and dimenhydrinate
• Allegra and Viagra
• Zyrtec, Zantac, Xanax, and Serax
• Claritin and Clarinex

Glucocorticosteroids (Intranasal):

• Beclomethasone
• Budesonide
• Flunisolide
• Fluticasone propionate and fluticasone furoate
• Triamcinolone
• Mometasone

Glucocorticosteroids MOA

• Inhibit inflammatory responses by reducing permeability of nasal mucosa to T lymphocytes and eosinophils, as well as decreasing mediator release
• Reduce inflammatory cells to decrease mucus and swelling

Glucocorticosteroids Adverse Reactions

• Nasal burning or stinging
• Throat irritation
• Nosebleeds
• Nasal candidiasis (fungal infection)

###Mast Cell Stabilizers

• Cromolyn sodium (Opticrom and Rhinaris)
• Nedocromil sodium (Alocril)
• Intranasal and ophthalmic use
• Reduces reactivity to allergens decreasing mast cell degranulation and inflammatory substance release
• Not effective for acute symptoms

Mast Cell Stabilizers Adverse Reactions

• Unpleasant taste
• Dry throat and cough
• Difficulty breathing
• Headache
• Nose bleeds
• Runny nose and sneezing
• Stinging, burning or irritation inside the nose

Leukotriene Receptor Antagonists

• Montelukast
• Controls allergic rhinitis symptoms
• Selective antagonist of the cysteinyl leukotriene D4 receptor

Leukotriene Receptor Antagonists Adverse Reactions

• Cough, hoarseness, or sore throat
• Headache
• Indigestion, heartburn, or stomach upset
• Runny nose
• Difficulty sleeping
• Dizziness
• Drowsiness
• Muscle aches or cramps
• Unusual dreams

Immunotherapy (Allergy Shots)

• Administered subcutaneously
• For perennial or seasonal allergies
• Lowers IgE levels and stimulates IgG production
• Administered as a series with increasing allergen concentration to reduce sensitivity

Angioedema

• Self-limiting, localized subcutaneous swelling from fluid extravasation into interstitial tissues
• Primarily affects loose connective tissue, including face, lips, mouth, throat, larynx, uvula, extremities, and genitalia
• Two types: mast cell-mediated/histaminergic and bradykinin-mediated

Angioedema Treatment

• If affecting the airways: intubation, epinephrine, O2, and IV fluids are necessary
• Acute allergic reactions: antihistamines or glucocorticoids
• ACE inhibitor induced: discontinue the ACE-inhibitor and substitute by an angiotensin receptor blocker if appropriate

Anaphylaxis

• Acute, potentially life-threatening, systemic hypersensitivity reaction from sudden release of mast cell mediators due to IgE mediated reactions (foods, drugs, insect stings)
• Severity ranges from self-limiting mild to fatal

Anaphylaxis Signs & Symptoms

• Skin and mucosal: Hives, itching, flushing, swollen lips, tongue, uvula, periorbital edema, conjunctival swelling
• Respiratory: Nasal discharge, nasal congestion, sneezing, itching of throat and ear canals, voice quality change, throat closure sensation, stridor, shortness of breath, wheezing, cough
• Gastrointestinal: Nausea, vomiting, diarrhea, crampy abdominal pain
• Cardiovascular: Hypotension (collapse), syncope, incontinence, dizziness, tachycardia, hypotension

Anaphylaxis Emergency Management

• Remove inciting cause (medication or allergen)
• Call for help
• Intramuscular (IM) injection of epinephrine
• Supplemental oxygen
• Volume resuscitation with IV fluids