44. The Science of Seasonal Allergies: Unpacking Allergic Rhinitis.
Evidence-Based Recommendations for Effective Management of Allergic Rhinitis...
Acchooo…. Acchooo…Acchooo
The sneeze at the outdoors, to which we are all accustomed; it's springtime in America, and Hayfever in the corner. Growing up in India in the 1980s and '90s, allergies were minimal, possibly the overwhelming infections much more common than the allergens and absent four seasons or not much pollen. When I moved to the US in late 1990, I noticed one thing during spring: the allergies got me badly. Itchy eyes are the first thing I have seen in Florida with possible grass pollen. After living in many states in the US, now in Virginia, for more than a decade, the symptoms of seasonal allergies, in fact, have gotten worse. I thought repeat exposures to the allergen one should be able to fight it out like the infections; however, as I have noticed, repeat seasonal allergies can feel stronger than previous years due to a phenomenon known as priming, where the immune system becomes more sensitive with each exposure to allergens like pollen, dust, or mold. Over time, repeated contact with these triggers leads to heightened immune responses—even small amounts can set off more intense symptoms. Environmental factors such as rising pollen counts, longer allergy seasons due to climate change, and increased air pollution can further amplify these reactions. Additionally, untreated or poorly managed allergic rhinitis can have a cumulative effect, making each allergy season feel worse than the last.
"Hay fever" is a historical term for allergic rhinitis. It was coined in the 1800s when people experienced sneezing and nasal symptoms during the hay-cutting season, mistakenly attributing it to hay. The real cause was pollen, and despite the name, it doesn't actually involve a fever.
The prevalence of allergic rhinitis based on physician diagnosis is approximately 15%; however, the prevalence is estimated to be as high as 30% based on patients with nasal symptoms. Allergic rhinitis is known to peak in the second to fourth decades of life and then gradually decline.
Allergies happen during the seasons, specifically in springtime or fall; some of the most common exposures to allergens are pollen, dander, mold, environmental pollution, etc. These are mostly IgE mediated(meaning Immunoglobulin E mediated), meaning we start to react when the allergens begin en route to the exposure, likely nasal or eye route. The IgE-mediated antibodies start to respond with the local allergen to nullify it. However, this constant barrage of pollen is consistently exposed to the nasal or eyes, creating this ripple effect and causing persistent rhinitis or allergic conjunctivitis symptoms.
Allergic rhinitis mainly consists of early and late-phase reactions. An IgE-mediated response against inhaled allergens that cause inflammation is present in early phase reaction. The initial phase happens within 5 to 15 min of exposure to the allergen, resulting in the degranulation of the host mast cells. This releases histamine, the primary mediator of allergic rhinitis, which induces sneezing through the cranial trigeminal nerve and increases nasal secretions by stimulating the mucus gland. Possible protective mechanism to get rid of the allergens. Other immune mediators, such as leukotrienes and prostaglandins, are also implicated as they act on blood vessels to cause nasal congestion.
The late-phase reaction happens four to six hours after the initial response, and an influx of cytokines, such as interleukins (IL)-4 and IL-13, from mast cells occurs, signifying the development of the late-phase response. These cytokines, in turn, facilitate the infiltration of eosinophils, T-lymphocytes, and basophils into the nasal mucosa and produce nasal edema with resultant congestion. It means there is a process going to keep the onslaught of the allergens, keeping inflammation chronic and symptoms ongoing.
The main acute symptoms include increased nasal secretions, sneezing, watery eyes, and nasal congestion. However, chronic symptoms include post-nasal drip, chronic nasal congestion, and nasal obstruction. Sometimes, it can present with an itchy throat, mouth, nose, and cough. When allergens get past the respiratory passages, they can influence wheezing or acute bronchoconstriction. This is likely reactive airway disease. Some people with a history of asthma can get it worsened by wheezing and coughing.
I see quite a patient in the office with allergic rhinitis, which can sometimes be confused with other viral infections. The most significant difference between allergic and Viral infections is that allergic rhinitis is immediate; however, the viral infection is more gradual. Also, rhinitis has more facial symptoms, including nasal congestion, itching of the eyes, etc. However, the viral effect causes generalized symptoms of weakness, fatigue, possible fevers, and generalized myalgias.
Prevention strategies :
Stay indoors if you have moderate to severe allergies to avoid the triggers. If moderate to severe allergies, getting a skin test for the allergies does help to prevent future attacks. I am allergic to springtime allergies, which worsen depending on the tree pollen. I found it very useful, especially because wearing a mask helps when prolonged outdoors. Most of the pollen is screened with a mask. Finally, taking a shower after being exposed to the outside does help to brush off the allergens. Precautions can be taken to avoid dust mites, animal dander, and upholstery, though this can require significant lifestyle changes that may not be acceptable for many. If removing a pet from the home is not feasible, isolating the pet to a single room in the house may be an option to minimize dander exposure. It may take up to 20 weeks to eliminate cat dander from the home, even after removing the animal. Allergen-impermeable bedding covers, washing sheets in hot water, and using a vacuum cleaner with high-efficiency particulate air (HEPA) filters may also lessen symptoms.
Medications :
Medications are key in treating the symptoms of acute rhinoconjunctivitis
A. Intranasal Steroids
B. Second Generation Anti Histamines
C. Anti Histamine Eye Drops
D. First-Generation Anti Histamines
E. Leukotriene Inhibitors (Monteleukast or Zafirleukast)
F. Decongestants (Pseudoephedrine or Oxymetazoline)
The first and foremost treatment shown in many trials is the effect of intra-nasal steroids and improvement with the allergic rhinitis. The following are the different kinds of Intranasal steroids. Fluticasone(Flonase OTC) is the best available OTC. Usually, starting around March 1st to Memorial Day is ideal for the medication if you suffer from seasonal allergies. Intranasal antihistamines, such as azelastine, have a rapid onset and are more efficacious than oral antihistamines in relieving nasal symptoms. They are recommended as first or second-line therapies for rhinitis and can be used in conjunction with topical nasal steroid sprays with a positive effect.
Allergic Rhinitis: Intranasal steroids
Fluticasone (Flonase) - Best
Momentasone( nasonex) - Best
Triamcinolone(nasocort)- Good
Budosenide (rhinocort)- Good
Beclomethasone (Qnasl)- Fair
If persistent, fluticasone (nasal steroid) and azelastine(nasal antihistamine) can help tackle severe allergic rhinitis better.
Per ARIA guidelines, the second most common usage is Second-generation antihistamines, which have improved H1 selectivity, are less sedating and have longer half-lives (12 to 24 hours) than first-generation ones. Fexofenadine has no sedating effects, but loratadine and desloratadine may be sedating at higher doses. Cetirizine has the most potential for sedation of all second-generation antihistamines. No one agent is recommended over others, as all have shown similar efficacy and safety profiles regarding symptom relief.
For both Itchy eyes and runny nose and nasal congestion - 2nd Generation Antihistamines
Fexofenadine (Allegra) is non-drowsy and ideal for daytime. It starts in 1 hr and lasts for 12–24 hrs. Avoid fruit juice (↓absorption) (My first preference)
Loratadine (Claritin) is non-sedating and has reasonable daily control. It starts working 1–3 hrs, lasts 24 hrs, and is less potent for severe symptoms.
Cetirizine (Zyrtec) is Fast-acting, effective nasal & eye relief in 1 hr, lasts 24 hrs, and May cause mild drowsiness in some.
Levocetirizine (Xyzal) is Potent and well-tolerated. It starts working in 1 hour and lasts 24 hours; it is More sedating than loratadine/fexofenadine.
First-generation antihistamines include diphenhydramine (Benadryl), chlorpheniramine, and hydroxyzine. They cross the blood-brain barrier, causing medications to have sedating effects. These agents also act on muscarinic receptors, causing side effects such as dry mouth, urinary retention, constipation, and/or tachycardia. Due to their side effect profile, these are the least favorite medications to use.
Allergic Conjunctivitis (Itchy eyes)
Olopatadine (Pataday, Patanol) Eye drops with Dual action: antihistamine + mast cell stabilizer (My 1st preference)
Ketotifen (Zaditor, Alaway) Eye drops OTC, good for itchy/red eyes
Azelastine (Optivar) Eye drops
The ARIA Guidelines (Allergic Rhinitis and its Impact on Asthma) emphasize that intranasal corticosteroids (INCS) are superior to oral antihistamines in controlling nasal symptoms, particularly congestion (Bousquet et al., JACI, 2008). Additionally, combining INCS with intranasal antihistamines has shown better efficacy than either agent alone in patients with moderate to severe allergic rhinitis, as supported by Seidman et al. (Otolaryngol Head Neck Surg, 2015). In a comparative study by Meltzer et al. (Allergy Asthma Proc, 2012), the combination of fluticasone and azelastine demonstrated a significantly greater improvement in total nasal symptom score (TNSS) and faster relief of ocular symptoms than fluticasone alone. Building on this evidence, the 2022 EAACI Guidelines by Kariyawasam et al. recommend initiating treatment with INCS in cases of persistent or moderate/severe allergic rhinitis and considering a combination therapy of INCS and intranasal antihistamines when monotherapy is insufficient.
Leukotriene receptor antagonists (LTRAs) such as montelukast and zafirlukast can be beneficial in patients with Allergic Rhinitis, but they are not as efficacious as intranasal corticosteroids. They are often used in combination therapy with other agents for severe or refractory symptoms.
For patients with ineffective avoidance measures and combination pharmacotherapy, allergen immunotherapy should be considered. Subcutaneous immunotherapy (SCIT) is a commonly used therapy. Weekly incremental doses are given for 6 to 8 months, followed by maintenance doses for 3 to 5 years. Typically, patients experience a prolonged protective effect, and therapy can be ceased.
Other Common drugs used during the Allergies :
Oral decongestants such as pseudoephedrine help relieve symptoms but are not recommended for extended daily use due to their side-effect profile causing elevated blood pressure.
Intranasal decongestants such as xylometazoline (Afrin) are alpha-agonists delivered directly to nasal tissue to produce vasoconstriction. Prolonged use of intranasal decongestants has a risk of causing rebound nasal congestion (rhinitis medicamentosa) and, therefore, should not be used for more than a week.
Sodium cromoglycate (Cromolyn) effectively reduces sneezing, nasal congestion, and nasal itching, so it is a reasonable option in addition to other modalities.
Surgical treatment is reserved for patients with nasal polyps causing intractable nasal obstruction or chronic sinus disease refractory to medical treatment.
Budesonide is the only FDA-approved agent for pregnant patients experiencing symptoms of allergic rhinitis.
Omalizumab, a monoclonal antibody, is beneficial in patients with Allergic rhinitis, although the cost associated with therapy is a limiting factor in its use.
Nasal saline can be another option in conjunction with other treatment modalities.
Newer treatments in the pipeline :
Dapilumab, a fully humanized monoclonal antibody, improved AR-related nasal symptoms in a recent randomized, double-blind, placebo-controlled trial. It works by inhibiting the signaling of IL-4 and IL-13, both key drivers of immune diseases.
Allergic rhinitis is one of the most common seasonal allergies affecting many adults during pollen season; Virginia is particularly known for it. I deal with itchy eyes and taking olopatadine drops as I write about this topic. Whether you're experiencing sneezing, a scratchy throat, or nasal discharge, knowing your options during the allergy season is essential. Based on the scientific guidelines, I have curated the medications available for treating Allergic rhinitis and conjunctivitis (itchy eyes and nose) to help make a better choice when purchasing these products. Remember to consult your doctor before starting any new treatments, as this information is for educational purposes only, and many medications are available over the counter. I hope the beautiful weather continues, allowing everyone to enjoy it without letting allergies diminish the quality of life.
Suman Manchireddy MD, FACP
Internal Medicine,
Leesburg, VA.
Email: Care@ReliantMD.com
Disclaimer: This is for purely informational and educational purposes only. Seek medical advice before starting any testing or treatment regimen. The data presented here has been extensively researched and condensed for a broader audience, and it should be viewed for educational purposes only. The blogger or blog has no affiliation with any pharmaceutical company.
References :
https://www.nature.com/articles/s41572-020-00227-0
https://www.ncbi.nlm.nih.gov/books/NBK538186/#
Count me in...Spring and Fall. Thank you for the update.