From the Guidelines
Antihistamines are not recommended as a primary treatment for sinusitis, as they do not address the underlying inflammation or infection that causes most cases of sinusitis. While they may help with allergy symptoms that sometimes accompany sinusitis, such as sneezing or itchy eyes, they can actually be counterproductive as they may thicken mucus and impair drainage 1. For acute bacterial sinusitis, antibiotics like amoxicillin (500-875mg three times daily for 5-10 days) or amoxicillin-clavulanate may be needed. For symptom relief, better options include:
- Nasal saline irrigation
- Intranasal corticosteroids like fluticasone (1-2 sprays per nostril daily)
- Decongestants like pseudoephedrine (30-60mg every 4-6 hours, not exceeding 240mg daily) for short-term use The exception is if your sinusitis is specifically triggered by allergies, in which case second-generation antihistamines like cetirizine (10mg daily) or loratadine (10mg daily) might help as part of your treatment plan, but they shouldn't be the primary treatment for sinusitis itself 1. A study published in 2020 found that the addition of antihistamines to antibiotics and corticosteroids significantly decreased nasal obstruction, but did not reduce total symptom scores or rhinorrhoea symptoms 1. Therefore, antihistamines should not be used as a primary treatment for sinusitis, but may be considered as an adjunctive treatment in cases where allergies are a contributing factor.
From the Research
Effectiveness of Antihistamines for Sinusitis
- Antihistamines are indicated to reduce rhinorrhea in allergic patients with sinusitis, but not in those with suppurative sinusitis 2.
- Antihistamines are effective in treating acute sinusitis only when a patient has concomitant allergies and is symptomatic during the allergy season or after infection has been ruled out as the primary cause of sinusitis 3.
- A systematic review found that antihistamines are one of the interventions for acute sinusitis, but the review does not provide specific information on their effectiveness 4.
Use of Antihistamines in Allergic Rhinitis
- Antihistamines are effective in allergic rhinitis, which comprises approximately 80% of rhinitis found in children and 30% in adults 5.
- Antihistamines antagonize the effect of histamine at the H1 receptor and their major clinical effects are related to this, providing relief from rhinorrhoea, itch, and sneezing, but having little effect on nasal obstruction 5.
- A study found that the addition of loratadine to standard treatment improved the control of some symptoms of sinusitis in patients with allergic rhinitis 6.
Specific Studies on Antihistamines and Sinusitis
- A multicentric, randomized, double-blind, placebo-controlled study found that loratadine improved the control of some symptoms of sinusitis, such as sneezing and nasal obstruction, in patients with allergic rhinitis 6.
- Another study found that antihistamines are inferior to corticosteroids in allergic rhinitis therapy, but may be used as a sole agent in mild, intermittent rhinitis or in combination with topical corticosteroids in more severe disease 5.