Infant drooling is a normal physiological process because babies lack the muscle control needed to manage their saliva. This natural flow often becomes more noticeable between three and six months of age as salivary glands become more active. When a baby is ill, it can appear that the amount of saliva has dramatically increased, leading to the common question of whether sickness causes more drooling. The observation is accurate: babies often appear to drool more when sick.
The Difference Between Saliva Production and Retention
The apparent increase in drooling during an illness is often not due to a significant spike in saliva production, but rather an issue with saliva retention. Babies continuously produce saliva, which they must swallow reflexively many times per hour to prevent it from pooling. Illnesses interfere with this routine swallowing mechanism, causing the saliva to leak out of the mouth.
Nasal congestion is a common factor that disrupts the swallowing process by forcing a baby to breathe primarily through the mouth. When nasal passages are blocked by mucus, the mouth must remain open to take in air, making it difficult to close the lips and swallow saliva efficiently. This mouth-breathing posture allows the saliva to passively dribble out, creating the impression of excessive drooling.
Additionally, throat pain or inflammation can make the act of swallowing uncomfortable. The baby may subconsciously avoid swallowing to prevent the sensation of pain, causing saliva to pool in the mouth until it overflows.
How Common Illnesses Affect Swallowing
Many common childhood infections directly impede a baby’s ability to swallow comfortably, leading to the overflow of saliva. Upper respiratory infections, such as the common cold, cause nasal congestion and post-nasal drip, which are significant obstacles to normal swallowing. The buildup of mucus in the back of the throat can trigger coughing or gagging, further interrupting the natural reflex to manage saliva.
Other diseases cause painful lesions or inflammation within the mouth and throat. Hand-Foot-and-Mouth Disease, for example, produces painful sores on the tongue, gums, and inside of the cheeks. These small ulcers create intense pain when the throat muscles move, making the baby refuse to swallow. Similarly, illnesses that cause a severe sore throat, such as tonsillitis or Strep Throat, lead to painful swallowing, a condition known as dysphagia. In these cases, the drooling serves as an indirect sign that the baby is trying to avoid discomfort associated with a throat infection.
When Increased Drooling Signals a Medical Emergency
While most instances of increased drooling with sickness are benign, certain accompanying symptoms require immediate medical attention. The most urgent concern is when the excessive drooling is sudden and is coupled with difficulty breathing. This combination can signal a severe, rapid swelling of the upper airway, such as from epiglottitis or a severe allergic reaction.
Parents should look for “red flag” symptoms like stridor, which is a high-pitched, noisy sound heard when the baby inhales, indicating an obstruction in the windpipe. An inability to swallow any liquids, paired with a high fever or an ill appearance, also warrants an immediate medical evaluation. Refusal to drink can quickly lead to dehydration, which may manifest as a lack of wet diapers for eight hours or crying without producing tears.