In our clinical work, we must encounter children with coughs that do not resolve for a long time, and their parents are anxious. Today we would like to talk about the causes of coughs that do not resolve in children.
First of all, let’s clarify the concept that a cough that lasts >4 weeks is called chronic cough. After that we have to think about the following causes.
I. Cough asthma
Also known as cough variant asthma, it is a specific type of asthma in which chronic cough is the main or only clinical manifestation. At the onset of bronchial asthma, about 5% to 6% have a persistent cough as the main symptom, mostly occurring at night or in the early morning, often as an irritating cough, which is often misdiagnosed as bronchitis at this time.
Diagnosis is based on.
1. Persistent or recurrent cough for more than 1 month, and often at night (or early in the morning), with little sputum and aggravated by exercise. Absence of clinical signs of infection, or ineffectiveness of longer-term antibiotic therapy.
2. relief of cough attacks with bronchodilators.
3. A personal history of allergy or a family history of allergy with a hyperreactive airway; allergen skin testing, etc., can be used as an auxiliary diagnosis.
II. Upper respiratory tract cough syndrome
A syndrome with cough as the main manifestation due to nasal diseases causing backflow of secretions to the postnasal and pharyngeal regions, or even backflow to the vocal cords or trachea. Since it is not clear whether upper airway-related cough is caused by postnasal drip irritation or direct inflammatory stimulation of upper airway cough receptors, the 2006 US Cough Diagnosis and Management Guidelines recommend replacing PNDS with upper airway cough syndrome (UACS), a common cause of chronic cough. In addition to nasal diseases, upper airway cough syndrome UACS is often associated with diseases of the pharynx, larynx, and tonsils, such as allergic or non-allergic pharyngitis, chronic tonsillitis, and laryngitis.
Diagnosis is based on.
1, cough as the main clinical manifestation, with or without postnasal drip influenza.
2.History of underlying nasal and pharyngeal diseases.
3. Cough relief after treatment for nasal and pharyngeal diseases.
C. Cough after respiratory tract infection
Cough after respiratory infection is the most common cause, and it is generally not easily misdiagnosed. its symptoms are also our most common. clinical manifestations of post-infection cough: patients mostly show an irritating dry cough or cough up a small amount of white mucus sputum, which can last for 3 to 8 weeks or even longer. there is no abnormality on X-ray chest X-ray (frontal and lateral or lung CT) examination. Post-cough is often self-limiting and usually resolves on its own. In the Chinese cough guidelines, no specific criteria are mentioned for the diagnosis of post-infectious cough.
Diagnosis is based on.
1. Persistent cough after the disappearance of cold symptoms.
2. No significant abnormalities on chest X-ray/CT examination.
3, Normal exertional spirometry and one-second rate.
4.No past history of chronic respiratory disorders.
5, Exclude other causes of chronic cough.
Other rare causes.
1. Foreign body aspiration: cough is the most common symptom following aspiration of foreign bodies from the airway, and foreign body aspiration is an important cause of chronic cough in children, especially those 1-3 years old. Studies have found that 70% of patients with airway foreign body aspiration present with cough, and other symptoms include decreased breath sounds, wheezing, and history of asphyxia. Once the foreign body enters the area below the small bronchus, there can be no cough, i.e. the so-called “silent zone”.
2. Drug-induced cough: Angiotensin-converting enzyme inhibitors are less commonly used in children, and some children with renal hypertension may have a cough induced by the use of such drugs as captopril. The mechanism may be related to bradykinin, prostaglandin, and substance P secretion. The cough is usually chronic and persistent, aggravated at night or when lying down, and can be significantly reduced or even disappeared after 3 to 7 days of drug withdrawal. β-adrenergic receptor blockers such as proguanil can cause bronchial hyperresponsiveness, so they may also lead to drug-induced cough.
3. Otogenic cough: 2-4% of the population has vagal ear branches. In this group, when lesions occur in the middle ear, the vagus nerve is stimulated and causes chronic cough. Otogenic cough is a rare cause of chronic cough in children.