Is Sublingual Immunotherapy (SLIT) recommended for seasonal allergies?

Sublingual Immunotherapy (SLIT) for Seasonal Allergies

Sublingual immunotherapy (SLIT) is recommended for patients with seasonal allergic rhinitis, particularly when administered in a pre-/co-seasonal regimen starting at least 8 weeks before pollen season. 1

Efficacy and Benefits of SLIT

SLIT has been demonstrated to be effective for seasonal allergic rhinitis through multiple high-quality studies:

• Significantly reduces both symptoms and medication requirements in allergic rhinitis 2, 3
• Shows disease-modifying effects with benefits lasting 3-5 years after discontinuation of treatment 1
• Most effective when used for at least 3 years to achieve long-term benefits 1, 4

Optimal Administration Protocol

The pre-/co-seasonal administration regimen is strongly supported by evidence:

• Treatment should begin at least 8 weeks before the pollen season 1
• Longer preseasonal treatment (up to 4 months) improves clinical efficacy 1
• Treatment continues throughout the pollen season and stops at the end of the season 1

Patient Selection

SLIT is appropriate for patients with:

• Moderate to severe seasonal allergic rhinitis symptoms 1
• Symptoms inadequately controlled with standard medications 1
• Confirmed IgE-mediated allergy through skin testing or specific IgE blood tests 1
• Either monosensitization or polysensitization to relevant seasonal allergens 1

Allergen Selection

• Single-allergen SLIT has shown good efficacy in both monosensitized and polysensitized patients 1
• Treatment should focus on clinically relevant allergens that correlate with the patient's history and are confirmed by testing 1
• Common seasonal allergens with proven SLIT efficacy include grass pollen, birch pollen, ragweed, and cypress pollen 5, 2

Safety Profile

SLIT has a favorable safety profile:

• Local reactions are common but typically mild and transient 1
• Most common adverse events affect the mouth/throat (18.1%) and nose (50.5%) 1
• Systemic reactions are rare compared to subcutaneous immunotherapy 1
• Can be safely administered at home after initial dose under medical supervision 1

Duration of Treatment

• Minimum recommended duration is 3 years for optimal long-term benefit 1
• Benefits may be seen within the first year but increase with continued treatment 4
• At least 2 years of treatment is required to show significant benefit for nasal symptoms 4

Comparison to Other Treatment Options

When discussing SLIT with patients, clinicians should:

• Explain the differences between SLIT and subcutaneous immunotherapy (SCIT) including risks, benefits, convenience, and costs 1
• Note that SLIT offers the advantage of home administration after initial doses 1
• Highlight that SLIT is the only treatment that may modify the disease course, unlike symptom-relieving medications 1, 6

Pitfalls and Caveats

• Efficacy varies by allergen and product; a product-specific evaluation is recommended 6
• Dose adjustments may be needed based on adverse events, treatment effectiveness, or allergen sensitivity 5
• Limited data exists on the efficacy of multiple-allergen SLIT; this approach should be considered experimental 1
• Pre-/co-seasonal regimens may have better economic and compliance benefits compared to continuous regimens 1

SLIT represents an effective, safe, and convenient option for patients with seasonal allergic rhinitis, with the potential to modify disease course and provide long-term symptom relief beyond the treatment period.