The diagnosis of acute sinusitis prompts countless number of antibiotic prescriptions per year. Although the vast majority of cases of acute sinusitis resolve without treatment, antibiotics are prescribed for an estimated 85% to 98% of cases presented to a primary care clinic.

Antibiotics, compared with placebo, do reduce treatment failures in bacterial sinusitis by almost one half (from 31% to 16%). If culture results are unavailable, the antibiotic should target the most common bacterial pathogens. These include S. pneumoniae, H. influenzae, and M. catarrhalis.

Antibiotic resistance is on the rise and almost half of S. pneumoniae is now resistant to penicillin, and the majority of both H. influenzae and M. catarrhalis are B-lactamase positive. The choice of antibiotic should take into account a number of factors, such as geographic prevalence of resistance patterns, predicted efficacy, cost, side effects, and ease of ‘‘use.’’

The American College of Physicians published practice guidelines for the treatment of acute sinusitis. This position publication was endorsed by a number of groups, including the Centers for Disease Control and Prevention, the American Academy of Family Physicians, the American College of Physicians, American Society of Internal Medicine, and the Infectious Disease Society of America.

In this publication they give the following practice guidelines:

1. Sinus radiography is not recommended for the diagnosis of uncomplicated sinusitis.
2. Acute bacterial sinusitis does not require antibiotic treatment, especially if symptoms are mild or moderate.
3. Patients with severe or persistent moderate symptoms and specific findings of bacterial sinusitis should be treated with antibiotics. Narrowspectrum antibiotics (including amoxicillin, doxycycline and trimethoprim- sulfamethoxazole) are reasonable first-line agents.

Amoxicillin is a reasonable first line antibiotic choice for both adults and children, unless there is a high prevalence of B-lactamase producing strains. The higher dose (90 mg/kg/day) is recommended for children at higher risk of amoxicillin resistance, such as those who attend day care, were recently treated with antibiotics, or are under the age of 2 years.

The addition of potassium clavulanate can also counter this antibiotic resistance. The most common side effects include abdominal cramping and diarrhea, which are quickly reversed upon discontinuation of the drug. Trimethoprim-sulfamethoxazole is an alternative antibiotic in penicillin-allergic individuals.

However, up to 20% of S. pneumoniae may be resistant to this alternative. In a meta-analysis of several randomized trials, folate inhibitors were found to be as effective as the newer, more costly antibiotics; however, even the investigators cede the limitations of their data, so this should be interpreted with caution.

In contrast to amoxicillin, doxycycline provides broader antibiotic coverage, including activity against B-lactamase producing strains of H. influenzae and M. catarrhalis. First generation cephalosporins, such as cephalexin and cefadroxil, do not provide adequate coverage against H. influenzae and should not be used.

Second generation cephalosporins, such as cefuroxime axetil and cefprozil, as well as third generation cephalosporins, such as cefpodoxime axetil, and cefdinir, are appropriate choices. The first ketolide, telithromycin, was initially indicated for acute sinusitis, but this was revoked after reports of severe hepatotoxicity.

The fluoroquinolones, including ciprofloxacin, levofloxacin, and moxifloxacin, offer broadspectrum antimicrobial coverage, and are all indicated for acute sinusitis. Because of the concern for adverse effect on the development of joints, these should be avoided in children.

These medications can also prolong the QT interval, so should be used with caution in patients at risk for arrhythmia. No controlled studies have examined the length of treatment. Generally, antibiotics should be prescribed for 10 to 14 days, or 7 days after the patient is symptom free.

If symptoms fail to improve in 48 to 72 hours, it is reasonable to switch to a second line antibiotic. In general, antihistamines are not recommended in the treatment of acute sinusitis unless the patient has underlying allergic rhinitis. However, antihistamines have been shown to decrease sneezing and rhinorrhea in the common cold.

Although topical and oral decongestants are often used in the treatment of the symptoms of sinusitis, no prospective trials have been performed. These agents do have a modest effect in decreasing nasal airway resistance, and in theory may widen the ostia and improve nasal ventilation.

Chronic use of topical decongestants beyond 3 to 5 days should be discouraged, as they may result in significant rebound hyperemia and rhinitis medicamentosa. Nasal corticosteroids have been shown to decrease the inflammatory process of the nasal mucosa after nasal antigen challenge, and can modify both the early and late allergic response.

As an extension, it is reasonable to consider that nasal corticosteroids may decrease the inflammatory response in sinusitis. Nasal corticosteroids have been studied as adjunctive therapy to antibiotic therapy and found significant reduction in several symptom scores; in addition, they show no increase in adverse events.

However, it should be noted that nasal corticosteroids do not have a Food and Drug Administration-approved indication for treatment of acute sinusitis. Surgical intervention of acute sinusitis is rare, but may be needed in the case of complications of sinusitis, or in those patients who continue to have severe symptoms and are unresponsive to medical therapy.

Chronic Sinusitis

Corticosteroids (CCSs) are potent anti-inflammatory agents, and as such, would seem to be a logical choice to treat chronic sinusitis. Although intranasal CCSs are unlikely to reach the paranasal sinuses, they do improve nasal congestion, which is often a significant symptomatic component in chronic sinusitis.

Intranasal CCSs have also been shown to shrink nasal polyps. These benefits, combined with their relatively safe profile, make topical intranasal steroids a reasonable adjunctive therapy. Systemic corticosteroids are also widely used in clinical practice.

Recently, a double-blind placebo-controlled trial of prednisolone, 50 mg daily for 14 days versus placebo, demonstrated improvement of sinonasal polyposis as measured by symptom scores, nasal endoscopy, and MRI. The use of antibiotic treatment in chronic sinusitis is quite controversial.

Patients with chronic sinusitis may also present with acute bacterial sinusitis, and in these patients antibiotics are indicated. Immunocompromised patients are at higher risk of a chronic infectious process, and may need to be treated with antimicrobial therapy.

However, often acute exacerbations may be caused by reasons noninfectious in nature, such as allergic or non-allergic rhinitis. In these cases, treating the underlying disease is more appropriate. Aspirin sensitivity is often present in patients with nasal polyps.

In patients with aspirin-exacerbated respiratory disease (AERD), aspirin desensitization, followed by long term treatment (650 mg twice a day), have demonstrated improvement of clinical outcomes and decrease in the requirement for systemic corticosteroids.

Cysteinyl leukotrienes are proinflammatory mediators, and are especially elevated in patients with chronic sinusitis and AERD. Several pharmacologic agents target disruption of this pathway, and are collectively known as leukotriene modifiers.

In a placebo controlled study of aspirin intolerant asthmatics, zileuton, one such leukotriene modifier, reduced polyp size and restored the sense of smell. Surgical management may be indicated in cases refractory to medical management.

In a randomized controlled study comparing medical versus combined medical and surgical treatment of nasal polyposis, medical treatment alone was often sufficient to treat most symptoms. However, if the primary complaint is nasal obstruction, despite corticosteroid treatment, surgical intervention is indicated.