Spasmodic croup is a respiratory condition characterized by the sudden onset of a harsh, seal-like barking cough, usually beginning abruptly in the middle of the night. This distinctive sound is caused by swelling and inflammation in the larynx and trachea, which narrows the airway. Spasmodic croup itself is not infectious; it is generally considered a non-infectious reaction, often linked to a child’s individual airway sensitivity, though it may occasionally follow a mild cold.
Spasmodic Croup vs. Viral Croup: Understanding the Difference
The confusion regarding contagiousness stems from the fact that there are two primary types of croup, one of which is highly transmissible. The most common form, viral croup, also known as laryngotracheobronchitis, is caused by a viral infection, most frequently the Parainfluenza virus. This type is indeed contagious and spreads through respiratory droplets, much like a common cold, often beginning with several days of cold symptoms and a fever.
Spasmodic croup, by contrast, is not caused by a direct viral infection of the airway. This distinction is apparent in the symptoms, as spasmodic episodes typically occur without any preceding signs of an upper respiratory infection or fever. The onset is typically abrupt, with a child often waking suddenly from sleep with the characteristic cough and noisy breathing, or stridor.
The key differentiator is the presence of fever and the speed of symptom development. Viral croup develops gradually over two to three days and is usually accompanied by a low-grade fever, signaling a systemic infection. Spasmodic croup lacks this fever and appears suddenly, reflecting a hypersensitivity or allergic-type response rather than an infectious process. This non-infectious nature explains why children who experience spasmodic croup often have recurrent episodes, as the underlying sensitivity remains.
Non-Infectious Triggers That Cause Spasmodic Attacks
Since the condition is not caused by a virus, spasmodic croup is instead related to specific non-infectious factors that trigger the airway’s hypersensitivity. One of the most common triggers is the rapid change in temperature or humidity, which can cause the sensitive tissues in the larynx to spasm and swell. Moving from a warm indoor environment to cool night air is a frequent catalyst for an episode, which is why attacks often occur after midnight.
Allergies and environmental sensitivities can also precipitate a spasmodic attack, leading some medical professionals to refer to it as allergic croup. Exposure to indoor irritants like dust, pet dander, or mold, or outdoor allergens such as pollen, can cause the airway inflammation that results in the barking cough. This allergic reaction causes swelling below the vocal cords without the signs of an acute viral disease.
Another significant physiological trigger is Gastroesophageal Reflux Disease (GERD), where stomach acid backs up into the esophagus and irritates the upper airway. This reflux irritation can cause inflammation and swelling in the laryngeal and tracheal tissues, leading to the spasmodic coughing fit. Post-nasal drip, involving mucus draining down the back of the throat, can similarly cause irritation that results in laryngeal spasms. Understanding these triggers allows caregivers to focus on environmental and dietary management rather than isolating the child.
Managing a Spasmodic Croup Episode
When a spasmodic croup attack begins, the immediate goal is to reduce the swelling in the airway and keep the child as calm as possible, as distress and crying can significantly worsen the spasms. Parental reassurance is paramount, as an anxious child will breathe faster and harder, which increases the turbulence of airflow through the already narrowed windpipe. Speaking in a soothing voice and cuddling the child can help slow their breathing and prevent the situation from escalating.
One of the most effective immediate interventions is exposure to cold air, which often helps to rapidly constrict the swollen blood vessels in the airway and reduce inflammation. Taking the child outside briefly into the cool night air, or having them breathe the air in front of an open freezer, can often provide quick relief. Alternatively, moist air can also be soothing; sitting with the child in a bathroom filled with steam from a hot shower can help relax the vocal cords and ease the cough.
While most spasmodic episodes are short-lived and improve with home remedies, caregivers must monitor the child for signs of respiratory distress that require immediate medical attention. These signs include stridor that persists even when the child is resting, or when the skin visibly pulls in around the ribs or neck with each breath (retractions). If the child’s lips or fingertips begin to turn blue, or if they become excessively lethargic, emergency medical services should be called. A physician may recommend a single dose of an oral corticosteroid, such as dexamethasone, but the primary focus for home management remains comfort and environmental control.