Prather Pediatric and Allergy Center - Ask Doctor Brent

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Title: Asthma Cough Syndrome



Research at the Mayo Clinic over the past ten years has shown that forty percent of asthmatics who were proven to be asthmatic by pulmonary function studies with mecholyl challenge tests and long term follow-up, never wheezed. This is startling because in the past we thought that to be called an asthmatic you had to wheeze. Now we find that some asthmatics (up to forty percent in this particular study) present with mainly a cough but never have a clear cut wheeze.

Typically the asthma cough syndrome is seen as a cough which is dry and non-productive. It occurs both day and night but is usually worse at night. It is also usually worse with exercise. It does not respond at all to routine cough medicines including strong cough suppressants such as codeine. It does respond to bronchodilator and anti-inflammatory medicines routinely used for asthma. It does not always clear immediately since it is a chronic condition and may take several weeks to totally clear. This is important to understand so that the medical plan will be followed compulsively and continued until the symptoms are clear. A few things which should be considered in the differential diagnosis of the asthma cough syndrome include pertussis syndrome. This is the once common disease, whooping cough, which is on the comeback trail in many parts of our country. This can be diagnosed by your doctor with certain lab tests and typically is a more choking cough occasionally with whoops on inspiration. There are changes in the blood count and nasal secretions which can sometimes make the diagnosis. The patient responds well to Erythromycin (antibiotic). The cough will usually run its course with or without therapy as opposed to a chronic asthma cough syndrome. Some patients with pertussis syndrome, though, can cough for several weeks.

Another condition in the differential diagnosis of asthma cough syndrome is psychogenic cough. This is sometimes called a "honking" cough. The patient will cough every few seconds two to three times in a row yet still carry on a conversation. There is no medical treatment for this condition; however, just helping the patient realize that it is a nervous "ticlike" reaction will usually help them to heal themselves. All three of these conditions are very tricky and should obviously be evaluated by your doctor. The important thing to remember is that some asthmatics present as only a chronic cough and if improperly diagnosed may never be placed on the proper therapy to control their chronic problem.