Unusual Asthma Symptoms
Health Conditions That May Worsen Asthma continued...
The possible reasons why allergic rhinitis and asthma are related are that:
- The nasal and bronchial membranes are made up of almost the same type of tissue.
- The nerves of the upper airway (nasal cavity) and the lower airway (bronchial tubes) are connected. Both the upper and lower airways are exposed to the same external environment during breathing. When allergens reach the nasal cavity there is stimulation of nerve endings in the nasal cavity. This stimulation causes reflex neural signals to be sent to the tissues of both the nasal cavity and the lower airways. In the nasal cavity, these signals cause accumulation of fluid and the formation of mucus, while in the bronchial tubes they cause bronchial constriction and possibly acute asthma. This is sometimes referred to as the naso-bronchial reflex.
- Nasal congestion causes mouth breathing. During mouth breathing, air bypasses the nose. The air is not filtered for allergens and irritating particles, and it is not warmed or humidified. This non-conditioned air is more likely to cause bronchial hyper-reactivity and result in asthma symptoms.
- Mucus from the nasal cavity may drip from the back of the nose into the throat, especially during sleep. This dripping mucus triggers bronchial inflammation and causes episodes of asthma at night.
For more information, see WebMD's article on Allergies and Asthma.
Sinusitis and Asthma
Over the years, doctors have noted an association between asthma and sinusitis. In fact, 15% of patients with sinusitis also have asthma (as opposed to 5% of the normal population). An astounding 75% of severely asthmatic patients also have sinusitis. Additionally, asthmatic patients often report that their symptoms worsen when they develop sinusitis. Conversely, when the sinusitis is treated, the asthma improves.
The reasons behind the association of asthma and sinusitis include:
- Sinusitis may activate a "sinobronchial reflex" and worsen asthma.
- The infected mucus from the sinuses may drain into the bronchial tubes and cause inflammation that results in bronchitis (sinobronchitis). This can worsen asthma.
For in-depth information, see WebMD's Sinusitis and Asthma.