Table of Contents
Prevention (Prophylaxis) of Allergies
Primary Prevention: Avoiding Sensitization
Primary prevention aims to prevent the immune system from becoming sensitized to an allergen in the first place.
Reducing Allergen Load Early in Life
- House dust mite allergens
- Use mite-proof mattress and pillow covers.
- Wash bedding at ≥60 °C.
- Avoid thick carpets, heavy curtains, and stuffed animals in the bedroom of at‑risk children.
- Pollen
- Keep windows closed during high pollen season, especially at night.
- Use pollen screens and, if possible, air filters.
- Change clothes and wash hair after spending time outdoors in pollen season.
Environmental and Lifestyle Factors
- Tobacco smoke
- No smoking during pregnancy and in the presence of children.
- Second-hand smoke increases the risk of asthma and allergic diseases.
- Air quality
- Avoid unnecessary exposure to strong chemical fumes (e.g., aggressive cleaners, solvents, perfumes).
- “Hygiene hypothesis” and microbiome
- Excessive disinfection and very “sterile” environments may impair healthy immune development.
- Normal contact with soil, animals, and other children (e.g., daycare, outdoor play) can support a balanced immune system.
Nutrition and Allergy Risk
- Breastfeeding
- Exclusive breastfeeding for about 4–6 months (if possible) lowers allergy risk in predisposed children.
- Introduction of complementary foods
- Early, controlled introduction of common allergenic foods (e.g., egg, peanut) in infancy, under pediatric guidance, may reduce risk of food allergy development.
- Balanced diet and microbiome
- High-fiber diet and regular consumption of fruits and vegetables support beneficial gut bacteria that modulate immunity.
Secondary Prevention: Avoiding Allergy Worsening
Secondary prevention targets people who are already sensitized (e.g., positive allergy test) or have mild symptoms, aiming to prevent progression to more severe disease (e.g., from allergic rhinitis to asthma).
Allergen Avoidance and Reduction
- House dust mites
- As above: encasings, washing, reducing dust collectors.
- Pollen
- Pollen forecasts and apps to time outdoor activities.
- Car windows closed; use pollen filters in cars.
- Animal dander
- Ideally avoid keeping the triggering animal; strict bedroom exclusion if complete avoidance is impossible.
- Mold
- Ensure adequate ventilation, repair water damage quickly, use dehumidifiers in damp rooms.
- Occupational allergens
- Protective clothing and masks, improving ventilation.
- Changing tasks or workplace if necessary (e.g., hairdressers with severe latex or hair dye allergy, bakers with flour dust allergy).
Early Treatment of Mild Symptoms
- Using appropriate medications early (e.g., nasal antihistamine for seasonal rhinitis) can:
- Improve quality of life.
- Reduce chronic inflammation.
- Lower the risk of developing asthma (the “allergic march”).
Symptomatic Therapy of Allergies
Symptomatic therapy alleviates or suppresses symptoms but does not change the underlying tendency to react allergically.
Antihistamines
Histamine is a key mediator in Type I immediate allergies. Antihistamines block its receptors (mainly H1 receptors).
- Effects
- Reduce itching, sneezing, runny nose, and hives.
- Weaken redness and swelling.
- Forms
- Tablets or drops: for hay fever, urticaria (hives), mild food reactions.
- Nasal sprays: for allergic rhinitis.
- Eye drops: for allergic conjunctivitis.
- Generations
- 1st generation: often sedating (e.g., drowsiness).
- 2nd/3rd generation: less sedating, preferred for long-term use.
Glucocorticoids (Corticosteroids)
These are strong anti‑inflammatory and immunosuppressive agents.
- Topical forms
- Nasal sprays for allergic rhinitis.
- Inhalers for allergic asthma.
- Creams/ointments for atopic dermatitis (neurodermatitis).
- Systemic forms (tablets, injections)
- For severe, acute allergic reactions when local therapies are insufficient.
- Principles of use
- Prefer local (topical) over systemic administration.
- Use lowest effective dose for the shortest possible time.
- Medical supervision is important due to possible side effects.
Additional Symptomatic Medications
Leukotriene Receptor Antagonists
- Block leukotrienes, another group of inflammatory mediators.
- Used mainly in allergic asthma and sometimes in allergic rhinitis.
- Often as an add‑on to inhaled therapies.
Mast Cell Stabilizers
- Prevent mast cells from releasing mediators.
- Example: cromoglycate.
- Used as eye drops or nasal sprays, sometimes as inhalation.
- Preventive use: must be applied regularly before and during exposure to allergens; not effective as acute “rescue” medication.
Decongestant Nasal Sprays
- Cause narrowing of blood vessels in the nasal mucosa.
- Quickly relieve nasal obstruction.
- Important: only for short-term use (a few days) because of risk of rebound congestion and mucosal damage.
Therapy of Specific Clinical Pictures
- Allergic rhinitis and conjunctivitis
- Antihistamines (systemic and/or local), nasal glucocorticoids, mast cell stabilizers, eye drops.
- Atopic dermatitis
- Intensive skin care with moisturizers.
- Short-term topical glucocorticoids; in special cases calcineurin inhibitors.
- Avoidance of irritants and known allergens.
- Allergic asthma
- Inhaled glucocorticoids and bronchodilators (e.g., beta‑2‑sympathomimetics).
- Environmental and allergen management.
Causal Therapy: Allergen-Specific Immunotherapy
Allergen‑specific immunotherapy (also called desensitization or “allergy shots”) is the only widely established treatment that can alter the course of certain IgE‑mediated allergies.
Principle
- The patient receives controlled, gradually increasing doses of the offending allergen.
- Goal: change the immune response so that:
- Less IgE and more protective IgG antibodies are produced.
- The activity of regulatory immune cells increases.
- Mast cells and basophils react less intensely.
Over time, this leads to reduced symptoms upon natural exposure to the allergen.
Indications
- Moderate to severe:
- Allergic rhinitis / conjunctivitis due to pollen (grass, tree pollen).
- Allergy to house dust mites.
- Allergy to insect venoms (bee, wasp), especially after systemic reactions.
- Sometimes for certain animal dander allergies, depending on guidelines and individual situation.
Food allergies are currently only rarely treated with classic immunotherapy; specialized protocols and research exist but are not yet general standard.
Forms of Immunotherapy
Subcutaneous Immunotherapy (SCIT)
- “Allergy shots.”
- Allergen extract injected under the skin, usually in the upper arm.
- Phases
- Build‑up phase: increasing doses at short intervals (e.g., once a week).
- Maintenance phase: stable dose at longer intervals (e.g., every 4–8 weeks).
- Total duration: usually 3–5 years.
- Must be performed by specially trained medical personnel.
- Patient remains under observation after each injection due to risk of systemic reactions.
Sublingual Immunotherapy (SLIT)
- Allergen given as drops or tablets under the tongue.
- Held under the tongue for a certain time, then swallowed.
- First dose under medical supervision; subsequent doses often self‑administered at home.
- Also used for pollen and mite allergies.
- Typically daily application over several years.
Effects and Benefits
- Reduction of symptoms and medication use during allergen exposure.
- Long‑lasting effect, often persisting years after therapy completion.
- Can reduce risk of:
- Progression from allergic rhinitis to asthma.
- New sensitizations to additional allergens (especially if started early).
Risks and Limitations
- Local side effects
- Redness, swelling, itching at injection site (SCIT).
- Itching, tingling, or mild swelling in the mouth (SLIT).
- Systemic reactions
- Generalized urticaria, asthma symptoms, blood pressure drops.
- Very rarely: anaphylactic shock.
- Hence, strict monitoring, emergency medications, and adherence to protocols are essential.
- Not suitable for all patients:
- Severe, uncontrolled asthma.
- Certain autoimmune diseases or severe immune deficiencies.
- Use of some medications (e.g., certain beta‑blockers) may be problematic.
Emergency Treatment of Severe Allergic Reactions
Severe generalized allergic reactions (anaphylaxis) require immediate measures. Prophylaxis and therapy include preparation for such emergencies in high‑risk individuals.
Adrenaline (Epinephrine) Auto-Injector
- Life‑saving first‑line medication in anaphylaxis.
- Injected into the lateral thigh muscle.
- Prescribed to patients with:
- History of anaphylaxis (e.g., to insect stings, food, medications).
- High‑risk allergen exposures that cannot be fully avoided.
Anaphylaxis Emergency Set
Typically includes:
- Adrenaline auto‑injector.
- Fast‑acting oral antihistamine.
- Glucocorticoid (e.g., as tablets or solution).
- In asthma patients: rapid‑acting inhaled bronchodilator.
Patients and their close contacts should be trained:
- To recognize early signs of anaphylaxis.
- In correct use of the auto‑injector.
- To call emergency services immediately.
Long-Term Management and Patient Education
Allergen Identification and Counseling
- Diagnostic allergy testing to identify specific allergens.
- Individual counseling:
- Which allergen sources to avoid.
- How to modify home, workplace, and hobbies.
- Interpretation and limits of “hypoallergenic” or “allergen‑free” products.
Self-Management and Action Plans
- Written action plans for:
- Daily management (medication schedule, avoidance strategies).
- Handling acute symptom worsening (e.g., asthma exacerbation).
- Emergencies (steps to take in anaphylaxis).
Psychological Aspects and Quality of Life
- Persistent symptoms, dietary restrictions, and fear of reactions can burden patients.
- Supportive measures:
- Patient support groups.
- Psychological counseling if anxiety or social withdrawal occur.
Summary of Strategies
- Prophylaxis
- Reduce allergen exposure and harmful environmental influences.
- Support balanced immune development (e.g., microbiome, breastfeeding, reasonable exposure to natural environments).
- Symptomatic therapy
- Medications to reduce or block the effects of mediators (antihistamines, glucocorticoids, etc.).
- Organ‑specific treatments (skin, eyes, nose, lungs).
- Causal therapy
- Allergen‑specific immunotherapy to modify the immune response and achieve long-term tolerance.
- Emergency preparedness
- Adrenaline auto‑injectors and clear action plans for patients at risk of anaphylaxis.
- Education and long-term management
- Empowering patients to understand their allergy, avoid triggers, use medications correctly, and maintain quality of life.