It is possible to experience diarrhea when you have a cold, though it is not considered a primary symptom of a common cold. While colds primarily affect the respiratory system, digestive upset can sometimes occur alongside them.
How Colds Can Lead to Diarrhea
One way a cold can lead to diarrhea involves excess mucus production. When an individual has a respiratory infection, mucus from the nasal passages and throat can be swallowed, potentially irritating the digestive tract and leading to loose stools.
The body’s immune response to a viral infection can also influence the digestive system. A viral infection triggers a systemic immune response, and this generalized activation can sometimes extend to the gut, impacting its environment. Research indicates that the gut microbiome plays a role in modulating the immune system, and an enhanced immune response, while fighting viruses, can sometimes intensify disease symptoms, including gastrointestinal upset.
It is also possible to experience a co-infection, where a person simultaneously has a cold virus and a separate gastrointestinal virus or bacterial infection. Certain viruses, such as some strains of influenza or coronaviruses, can cause both respiratory and gastrointestinal symptoms, including diarrhea. Additionally, some over-the-counter medications taken for cold symptoms might contribute to digestive upset.
Other Common Causes of Diarrhea
While a cold can sometimes be associated with diarrhea, many other conditions commonly cause this symptom. Gastroenteritis, often referred to as the “stomach flu,” is a very common cause of diarrhea, typically characterized by loose, watery stools, abdominal cramps, nausea, and vomiting. Although primarily affecting the digestive system, gastroenteritis can sometimes present with mild fever or body aches, which might be confused with cold symptoms.
Food poisoning is another frequent cause of sudden diarrhea, resulting from consuming contaminated food or water. Symptoms, including diarrhea, abdominal cramps, nausea, and vomiting, can appear within hours to several days after exposure. The onset and severity of food poisoning symptoms can vary depending on the specific germ involved.
Certain medications, including some taken for cold symptoms, can cause digestive side effects. For instance, some decongestants or cold and flu relief medications may list mild nausea or diarrhea as a common side effect. Antibiotics, often prescribed for secondary bacterial infections that can follow a cold, are a well-known cause of diarrhea because they disrupt the natural balance of beneficial bacteria in the intestines. This antibiotic-associated diarrhea can occur during treatment or even weeks afterward.
Dietary factors can also trigger diarrhea, independent of a cold. Foods high in fat, spicy dishes, and artificial sweeteners like sorbitol or xylitol can irritate the digestive system in some individuals. Lactose intolerance, where the body struggles to digest sugar found in dairy products, and excessive caffeine intake can also lead to loose stools.
When to Consult a Doctor
While most cases of diarrhea accompanying a cold are mild and short-lived, certain signs warrant medical attention. For adults, a doctor should be consulted if diarrhea persists for more than two days without improvement. In children, especially young ones, medical advice is recommended if diarrhea does not improve within 24 hours.
Dehydration is a significant concern with diarrhea, particularly in vulnerable populations. Signs of dehydration in adults include excessive thirst, dry mouth, decreased urination, severe weakness, dizziness, or lightheadedness. For infants and young children, symptoms like no wet diapers for several hours, dry mouth, crying without tears, sunken eyes, or unusual drowsiness indicate a need for immediate medical assessment.
Other alarming symptoms that necessitate a doctor’s visit include a high fever (above 101°F or 38.3°C in adults, or 102°F/39°C in children), severe abdominal or rectal pain, bloody or black stools, or persistent vomiting that prevents keeping fluids down. Infants under six months of age with diarrhea should always be seen by a doctor. Additionally, individuals with weakened immune systems or underlying health conditions should seek quicker medical assessment if they experience diarrhea, as they are more susceptible to complications.