Other Uncommon Causes of Chronic Cough
A non-pulmonary, uncommon cause of chronic cough is a vascular ring, a congenital anomaly in which blood vessels encircle and potentially constrict the esophagus and/or trachea. The most common type is a double aortic arch, but a right aortic arch or pulmonary artery sling is also possible. These coughs sound harsh and are usually accompanied by stridor, dyspnea and feeding problems. Workup includes an echocardiogram, a CT angiogram, and possibly a bronchoscopy to determine the extent of the airway narrowing. In symptomatic patients, surgery is indicated for correction.
Another congenital malformation that can cause chronic cough is a tracheoesophageal fistula, which occurs in about one in 3500 live births, commonly linked to trisomy disorders and VACTERL. Several types of tracheoesophageal fistula exist, and H-type fistula is associated with late onset symptoms. The cough can be wet or dry and sometimes sounds like barking because of the associated airway collapse. Patients often have recurrent pneumonia, bronchitis, and cough or cyanosis with feeding. Workup should include an upper gastrointestinal series but not with barium, Bhatia said, because that can cause pneumonitis. Instead, the series should be done with a thickened water-soluble contrast material, and a bronchoscopy may be indicated as well.
Though common as a condition in adults, gastroesophageal reflux disease (GERD) is a rare, but possible, cause of chronic cough in children. More often, the reflux is the result of the cough rather than the cause. The most sensitive tool for assessing GERD is esophageal 24-hour pH/impedance reflux monitoring. However, treatment of the reflux for cough is not recommended unless the patient has clinical features of GERD, including dystonic neck posturing in infants, heartburn, regurgitation, or other symptoms. If the patient has clinical symptoms, then treatment is acid suppressive therapy for 4-8 weeks, followed by a clinical reassessment.
An uncommon cause of chronic cough with no biological mechanism is habit cough. Habit cough is most easily distinguished from other coughs by its sounds, a “large, loud, honking noise,” Bhatia said. It also lacks a clear trigger and is usually absent during sleep, but it can be continuous during the day. Frustratingly, the patients themselves often don’t seem bothered by the cough, but “it’s very disruptive in the school and everywhere else,” Bhatia said. Families and/providers will often have tried multiple treatments and seen no improvement with habit cough.
The first thing to do with habit cough is reassure the family that there’s nothing serious going on because they are often worried by this point. Several non-pharmaceutical treatments can be effective, such as suggestion therapy or the “warm water technique,” in which the patient takes a sip of warm water every time they feel the urge to cough. “If they’re able to break the cycle, most of the time, they are fine,” Bhatia said. In rarer cases, more involved behavioral interventions may be indicated, such as a psychology referral if an underlying anxiety or other behavioral disorder is contributing.
Newer Causes of Cough
Two more recent causes of cough to watch for are long COVID and e-cigarette or vaping product–associated lung injury (EVALI), Bhatia said. The clearest sign of EVALI is a history of e-cigarette/vaping exposure, but clinical symptoms include a dry cough that occurs with dyspnea and chest pain. A chest x-ray may show diffuse, hazy, or consolidative opacities. Sometimes antibiotics or steroids can be helpful, but the evidence isn’t strong, and the most effective treatment is stopping e-cigarette use. Less commonly, passive exposure to vaping can also be associated with EVALI.
The most recent research on long COVID suggests that about 10-20% of children with acute COVID develop long COVID, and about a quarter of these patients develop a chronic dry cough. It’s often associated with fatigue and shortness of breath, which can be assessed with cardiopulmonary exercise testing. Sometimes a short trial of inhaled steroids can help.
Bhatia also mentioned a handful of other uncommon causes of chronic cough that most American pediatricians are unlikely to see: Childhood interstitial lung disease, tuberculosis, use of Angiotensin-Converting Enzyme inhibitors, and a build-up of ear wax via the Arnold’s nerve reflex.