Cough is one of the most common symptoms in childhood. In most cases it occurs as part of a viral respiratory infection, but it can have different causes depending on where the irritation or inflammation is located. This information sheet explains typical cough patterns, what is usually normal, and which warning signs should be assessed by a clinician.

1. What is a cough?

A cough is not a disease in itself. It is a protective reflex that helps clear mucus, irritants and (occasionally) foreign material from the airways.

In everyday terms, cough is often described as:

• Dry (non-productive) cough
• Wet (productive) cough

2. Dry vs. wet cough

Dry cough (irritating/non-productive)

Typical features:

• little or no mucus
• often scratchy, barking or painful
• frequently worse at night
• common at the start of a viral infection

Common causes:

• viral cold
• irritation of the airway lining
• dry or cold air
• laryngeal inflammation (e.g. croup)

Wet cough (productive)

Typical features:

• mucus in the airways
• a “rattly” sound with breathing or coughing
• often appears after a few days of a cold

Common causes:

• cold in its later phase
• acute bronchitis

Note: A wet cough can be useful because it helps move mucus out of the airways.

3. Where does the cough come from? – Causes along the airway

Cough can be triggered at different levels of the respiratory tract. The location often influences the sound of the cough and the associated symptoms.

Upper airway

• Throat/pharynx (common cold): Mucus dripping and irritation in the throat can trigger coughing, often together with a runny nose and sore throat.
• Larynx/vocal cords (croup): Swelling around the vocal cords may cause a barking cough, hoarseness, and symptoms that can worsen at night.

Central airway

• Trachea (tracheitis): Often a dry, painful cough, sometimes described as burning discomfort behind the breastbone.
• Large bronchi (acute bronchitis): Inflammation and mucus in the bronchi typically cause a wet cough and occasionally mild fever. The cause is usually viral.

Lower airway and lungs

• Small airways/bronchioles (bronchiolitis): Mainly in babies and young toddlers. Possible signs include rapid or laboured breathing, wheeze and poor feeding.
• Lung segment/lobe (pneumonia): Can present with fever, cough and a noticeably unwell child. Assessment by a clinician is required.

4. Other important causes

• Wheeze/obstructive bronchitis: Narrowing of the airways can cause coughing together with wheeze and a prolonged breath out (prolonged expiration). This can occur with viral infections and in children with an asthma tendency.
• Strep throat (streptococcal tonsillitis): Cough can occur due to throat irritation, but it does not necessarily originate from the lungs.
• Foreign body inhalation (especially in toddlers): Sudden coughing that starts during eating or playing, often without typical cold symptoms. Sometimes breathing sounds are reduced on one side. This is an emergency and needs immediate medical assessment.
• Very rare congenital causes: In exceptional cases, persistent or treatment-resistant cough may be due to congenital conditions, e.g. vascular rings/sling that compress the airway (such as pulmonary sling or double aortic arch) or structural airway anomalies. Possible clues include symptoms from early infancy, poor weight gain, recurrent unusual infections, or lack of response to usual treatments.

5. Whooping cough (pertussis)

Whooping cough is now uncommon thanks to successful vaccination programmes. However, it can still occur, particularly in unvaccinated or incompletely vaccinated infants and adolescents.

6. Different cough patterns

• Wet, “rattly” cough: Suggests mucus in the airways, typical of bronchitis or the later phase of a cold.
• Dry cough: Often due to irritation of the airways or the early phase of an infection.
• Coughing fits: Repeated strong bouts of coughing. In small infants, this can be associated with breathing difficulty and even brief pauses in breathing (apnoea), which is a classic concern in pertussis.
• Cough leading to vomiting or “spitting up” mucus: Strong coughing can irritate the throat (pharyngeal irritation) and trigger gagging, vomiting, or expelling mucus—particularly common in younger children.
• Cough with increased drooling: If there is marked drooling together with difficulty swallowing, discomfort, or distress, this can be a sign of a foreign body lodged in the oesophagus (swallowed foreign body). Prompt medical assessment is required.

7. How long is a cough “normal”?

A cough can persist even when the child otherwise seems well again.

• Common cold: about 1–2 weeks
• Acute bronchitis: about 2–3 weeks, sometimes up to 4 weeks

Note: A lingering cough does not automatically mean there is a serious illness, but it should be reviewed if it is prolonged or worsening.

8. When should a child be assessed by a clinician?

Please seek medical advice urgently if your child has any of the following:

• breathing difficulty, rapid breathing, or chest retractions
• persistent high fever
• child is clearly unwell, unusually sleepy, or hard to rouse
• poor feeding or refusing fluids (especially infants)
• cough lasting longer than 4 weeks
• blood in mucus/phlegm
• suspected inhaled or swallowed foreign body
• coughing fits with colour change, apnoea, or significant breathing problems