Speaker's Highlight

• Don Sin University of British Columbia, St. Paul Hospital (Canada)
  Kenneth R. Chapman Toronto General Hospital Research Institute (Canada)
• Parameswaran Nair McMaster University (Canada)
  Carolyn Calfee UCSF (U.S.A.)
• Gregory P. Downey University of Colorado School of Medicine (U.S.A.)
  David A. Schwartz University of Colorado School of Medicine (U.S.A.)
• Neil Schluger Tuberculosis Control Branch, California Department of Public Health (U.S.A.)
  Nick Kim Critical Care & Sleep Medicine, University of California San Diego (U.S.A.)
• Nicola Hananiah Baylor College of Medicine (U.S.A.)
  Jae-Joon Yim Seoul National University College of Medicine (Republic of Korea)
• Koichiro Asano Tokai University School of Medicine (Japan)
  Diahn-Warng Perng Taipei Veterans General Hospital (Taiwan)
• Konstantinos Kostikas University of Ioannina (Greece)
  Karin Klooster University Medical Center Groningen (Kingdom of the Netherlands)

• Allergen Immunotherapy In Respiratory Allergy Care

  Respiratory allergies can turn ordinary exposure to pollen, house dust mites, mold, or animal dander into persistent sneezing, nasal blockage, itchy eyes, coughing, and wheezing. Medication can control these symptoms, but some patients continue to experience flare-ups, sleep disruption, or reduced quality of life despite appropriate treatment.

  Allergen immunotherapy takes a different approach. Instead of suppressing symptoms temporarily, it gradually introduces carefully measured amounts of a specific allergen to reduce the immune system’s exaggerated response. This disease-modifying strategy is used mainly for allergic rhinitis and selected cases of allergic asthma.

  For respiratory specialists, immunotherapy is most effective when it is based on accurate diagnosis, realistic expectations, and coordinated long-term follow-up. Skin testing or allergen-specific IgE testing helps identify clinically relevant triggers, while lung function assessment is important when asthma is present.

  How Immune Desensitization Works

  People with respiratory allergies produce an inappropriate immune response after inhaling otherwise harmless substances. Allergen exposure activates immunoglobulin E, mast cells, and inflammatory pathways that produce congestion, sneezing, bronchial narrowing, and other symptoms. Immunotherapy aims to retrain this response over time.

  During treatment, repeated allergen exposure promotes immune tolerance. Blocking antibodies such as immunoglobulin G4 may increase, while inflammatory signaling and sensitivity of target tissues can decline. The process is gradual, so improvement may develop over several months rather than after the first dose.

  The strongest clinical role is in allergic rhinitis, particularly when symptoms are persistent, medication is insufficient, or treatment causes unwanted effects. It may also reduce the risk of asthma exacerbations in carefully selected patients whose asthma is stable and clearly linked to an identified allergen.

  Who May Benefit From Treatment

  Candidates usually have symptoms that match a confirmed sensitization. A positive allergy test alone is not enough; the suspected allergen must also be relevant to the patient’s exposure pattern and clinical history. For example, sensitization to grass pollen is more meaningful when symptoms reliably worsen during the grass-pollen season.

  Immunotherapy may be considered for patients with seasonal hay fever, perennial allergic rhinitis caused by house dust mites, or selected allergic asthma cases. It can be especially valuable when symptoms interfere with work, school, exercise, or sleep, or when long-term reliance on antihistamines, nasal corticosteroids, or inhaled medication is undesirable.

  Treatment requires shared decision-making. Patients should understand that the course commonly lasts three to five years, benefits accumulate gradually, and regular attendance matters. Uncontrolled asthma, certain immune disorders, pregnancy-related considerations, and the use of beta-blockers require individualized assessment before therapy begins.

  Injection And Tablet-Based Options

  Subcutaneous immunotherapy involves injections administered in a medical setting. The dose is increased during an escalation phase and then maintained at a level designed to produce lasting immune tolerance. Because systemic allergic reactions can occur, patients are observed after injections and clinics must have emergency treatment available.

  Sublingual immunotherapy uses tablets or liquid extracts placed under the tongue. The first dose is generally given under clinical supervision, while subsequent doses may be taken at home when appropriate. This route avoids repeated injections but still requires adherence and awareness of possible local mouth or throat reactions.

  The most suitable route depends on the allergen, approved products, patient age, medical history, access to care, and preference. Sublingual treatment can be convenient for people who prefer home administration, whereas injection therapy may offer broader customization in some clinical settings.

  Consideration	Subcutaneous Immunotherapy	Sublingual Immunotherapy
  Administration	Injections in a clinic	Tablet or extract under the tongue
  Early treatment	Frequent dose-building visits	First dose supervised, then home use may be possible
  Common reactions	Local swelling, occasional systemic reactions	Mouth or throat itching, mild local irritation
  Monitoring	Observation after each injection	Education and follow-up remain essential
  Main advantage	Established option with flexible dosing in some settings	Convenient needle-free administration
  Main limitation	Time, travel, and injection-related concerns	Product availability and daily adherence

  Safety, Monitoring, And Asthma Control

  Most adverse effects are mild and localized. Injection-site swelling may occur with subcutaneous therapy, while oral itching or throat discomfort is common with sublingual products. Severe systemic reactions are uncommon but potentially serious, which is why treatment should follow product-specific protocols and emergency preparedness standards.

  Asthma control deserves particular attention. Immunotherapy should not be administered when asthma is poorly controlled because the risk from a systemic reaction may be greater. Symptom review, peak flow or spirometry when indicated, and medication assessment help clinicians determine whether it is safe to continue.

  Patients should report breathing difficulty, widespread hives, dizziness, vomiting, or rapidly developing symptoms after treatment. Clear written instructions and appropriate emergency medication, including epinephrine when prescribed, support safer care. Follow-up also helps distinguish expected local reactions from signs requiring urgent evaluation.

  Combining Immunotherapy With Daily Management

  Immunotherapy does not replace allergen avoidance or symptom medication at the beginning of treatment. Saline rinses, intranasal corticosteroids, antihistamines, inhaled therapies, and environmental measures may still be needed while immune tolerance develops. A coordinated plan prevents patients from stopping effective treatment too early.

  Environmental control should be practical rather than excessive. Measures may include reducing bedroom dust-mite exposure, improving ventilation, repairing moisture problems, keeping windows closed during high pollen periods, and avoiding tobacco smoke. The value of each measure depends on the confirmed trigger and the patient’s living conditions.

  Progress can be assessed through nasal and chest symptoms, rescue medication use, sleep quality, activity levels, exacerbations, and patient-reported quality of life. A reduction in symptom burden is useful, but a broader view helps determine whether treatment is delivering meaningful daily benefits.

  Building A Reliable Treatment Plan

  Effective allergen immunotherapy depends on selecting the right patient and maintaining continuity across allergy, respiratory, and primary care services. Before treatment, clinicians should document the target allergen, baseline symptoms, asthma status, current medication, and any factors that could affect safety or adherence.

  Patients benefit from a clear schedule and realistic milestones. Missed doses may require adjustment, particularly with injection therapy, and treatment should not be restarted casually after a prolonged interruption. Communication between the clinic and patient is essential when illness, pregnancy, medication changes, or worsening asthma occurs.

  Practical priorities include:

  • Confirm the relationship between allergen sensitization and respiratory symptoms.
  • Stabilize asthma and review lung function before starting therapy.
  • Choose injection or sublingual treatment according to safety, access, and adherence.
  • Continue appropriate nasal or inhaled medication while benefits develop.
  • Record symptom changes, reactions, missed doses, and quality-of-life outcomes.

  Respiratory medicine teams can improve results by combining evidence-based immunotherapy with education and structured follow-up. When diagnosis, safety monitoring, and patient participation align, allergen immunotherapy can reduce the burden of allergic rhinitis and support better long-term respiratory health. Explore current clinical guidance and discuss individualized treatment pathways with a qualified allergy or respiratory specialist.

  Richard Russell Nuffield Department of Clinical Medicine, University of Oxford (United Kingdom)
• Mona Bafadhel King’s College London (United Kingdom)
  David Jackson Guy’s and St Thomas’ Hospital, King’s College London (United Kingdom)
• James Chalmers University of Dundee (United Kingdom)
  David Price University of Aberdeen (United Kingdom)