Acute onset of a cough, stridor and dyspnea in a child is mostly due to –
"Choking and coughing episodes accompanied by wheezing are highly suggestive of airway foreign body" - Nelson
"Foreign body aspiration should always be considered as a potential cause of stridor and airway obstruction in children".  --- O.P. Ghai
Foreign body aspiration

Infants and toddlers use their mouths to explore their surroundings.
So, they are very prone to aspirate a foreign body.
The most common age group is 6 months to 4 years.
Most common foreign body aspirated is nuts (peanuts).
Most airway foreign bodies lodge in a bronchus (right more than left).

Clinical manifestions
Three stages of symptoms may results : -


Stage I - Initial event → Violent paroxysm of coughing (a most common symptom), choking, gagging and wheeze immediately after aspiration. If the obstruction is complete, child may be unable to vocalize (aphonia) and there may be cyanosis. If the obstruction is incomplete drooling and stridor may occur.
Stage II Asymptomatic → The foreign body becomes lodged, reflex fatigue and immediate irritating symptoms subside. This stage is most treacherous and account for a large percentage of delayed diagnosis and overlooked foreign bodies.
Stage III - Complications → Obstruction, erosions or infection can cause fever, hemoptysis, pneumonia and atelectasis. The most serious complication of foreign body aspiration is complete airway obstruction.
Foreign body
Acute Asthma
Aspiration pneumonitis
Primary complex