Intermittent: Patients have episodic illness, with extended symptom-free periods. Episodes are most commonly triggered by viral respiratory infections or exposure to an environmental allergen or irritant.

Chronic: Patients experience virtually daily symptoms and, in the absence of continuous therapy, do not have extended symptom-free periods.

Seasonal allergic: Patients experience virtually daily symptoms during an inhalant allergy season. Allergens and patterns will vary with the geographic region. Seasonal symptoms may be in reaction to molds, pollens, or a combination of both.

There is potential overlap among these clinical patterns. For example, patients with chronic disease often have intermittent exacerbations from viral respiratory illness and may have seasonal allergic exacerbations. Nonetheless, identification of the clinical pattern contributes to the determination of a therapeutic strategy.

Severity, as assessed by degree of morbidity, is independent of the clinical pattern. Both intermittent and chronic disease may range from relatively benign to life threatening. Severity should be judged by the frequency and intensity of urgent care requirements, missed school or work, and interference with activity or sleep.