The Immune System's Protective Response
When you become ill, your immune system launches a protective response against invading viruses or bacteria. This can cause widespread inflammation throughout your body, affecting various mucous membranes, including those in your eyes, nose, and sinuses. This inflammation and heightened immune activity can directly lead to increased tearing.
How Inflammation Affects Tear Ducts
Your tear drainage system is a small, but integral, network of ducts that channel tears from the eye's surface into your nasal cavity. When you have a respiratory infection like a cold or flu, the inflammation and swelling of your nasal passages can block these tear ducts. With the normal drainage route obstructed, tears can't flow away properly and instead build up and overflow from your eyes, causing them to appear watery. This is one of the most common reasons behind watery eyes when you are sick.
The Role of Reflex Tears
Beyond simple blockage, watery eyes are also a result of reflex tearing. This is a special type of tear produced quickly and in large volumes by the body to help flush away irritants. When your eyes are irritated by the underlying illness or inflammation, they produce these reflex tears as a defense mechanism to sweep away any pathogens or debris. This natural process is a key reason you notice excessive tearing during a cold.
Common Illnesses and Watery Eyes
Several common illnesses and conditions are known to cause watery eyes as a side effect.
The Common Cold and Flu
As mentioned, the common cold and flu are prime culprits. The viruses behind these illnesses cause inflammation and congestion, affecting both your nasal passages and tear ducts. This can result in both blocked drainage and reflexive tearing.
Conjunctivitis (Pink Eye)
Often called an "eye cold," viral conjunctivitis is a common cause of watery eyes, especially during or after a respiratory infection. It involves the inflammation of the conjunctiva, the clear membrane covering the white part of your eye. Symptoms include redness, irritation, and a watery or mucus-like discharge. It's highly contagious and can be spread by touching your face or eyes after contact with the virus.
Sinus Infections (Sinusitis)
When a cold lingers, it can sometimes develop into a sinus infection. The inflammation from a sinus infection can place significant pressure on the tear ducts, leading to watery eyes and puffy eyelids. The pain and pressure are often felt around and behind the eyes, making watery eyes a predictable symptom.
Dry Eyes
Paradoxically, being sick can also exacerbate or trigger dry eyes, which in turn causes excessive tearing. Decongestants and antihistamines used to treat cold symptoms can dry out the eyes, and in response, your eyes produce a flood of reflex tears to compensate.
Watery Eyes: Cold or Allergies? A Comparison
It can be difficult to tell if your symptoms are from a viral infection or an allergic reaction. Here is a table to help distinguish between the two based on typical symptoms.
| Symptom | Common Cold | Allergies |
|---|---|---|
| Cause | Virus (e.g., rhinovirus, adenovirus) | Airborne allergens (e.g., pollen, dust, pet dander) |
| Tearing | Present; can be caused by blocked tear ducts | Present; caused by histamine release |
| Itching | Absent or minimal | Often intense itching of eyes and nose |
| Discharge | Clear and watery | Clear, watery, and sometimes sticky |
| Other Symptoms | Body aches, sore throat, cough, fatigue | Sneezing, post-nasal drip, no fever |
| Contagious? | Yes | No |
When to Be Concerned and See a Doctor
While watery eyes when sick are typically harmless and temporary, there are certain signs that indicate a more serious issue requiring medical attention. Seek professional help if you experience any of the following:
- Eye pain: Severe or persistent pain around or in the eye.
- Vision changes: Blurred vision, double vision, or a sudden decrease in vision.
- Thick discharge: Yellow or greenish pus-like discharge, which could indicate a bacterial infection.
- Light sensitivity: Increased sensitivity to bright light (photophobia).
- Foreign body sensation: A feeling that something is constantly in your eye.
- Prolonged symptoms: Watery eyes that last longer than your other illness symptoms, particularly if they do not improve after a week.
How to Treat Watery Eyes When Sick
For most mild cases of watery eyes from a cold or flu, you can find relief at home. The following methods can help ease discomfort and manage symptoms:
- Use Warm Compresses: Applying a warm, damp cloth over your eyes for 5-10 minutes several times a day can help soothe irritation and clear blocked glands.
- Try Artificial Tears: Lubricating eye drops can help moisturize the eye's surface, especially if dryness is triggering the excess tearing. Choose a preservative-free option if you use them frequently.
- Stay Hydrated: Drinking plenty of fluids can help thin mucus throughout your body, including in your nasal passages, which can improve tear drainage.
- Consider Decongestants: For nasal congestion, an over-the-counter decongestant can help reduce swelling and clear the tear ducts. However, be aware they can also contribute to dry eyes.
- Rest Your Eyes: Avoid excessive screen time and give your eyes plenty of rest, as eye strain can exacerbate irritation.
- Practice Good Hygiene: Avoid rubbing your eyes, and wash your hands frequently to prevent the spread of infection, especially if conjunctivitis is suspected.
- Use a Humidifier: Running a humidifier can add moisture to dry indoor air, which can be irritating to your eyes, especially during winter months.
Conclusion
In conclusion, if you are sick and your eyes are watering, it is a very common and normal symptom. It is a sign that your body is fighting an infection, causing inflammation and congestion that affects tear production and drainage. While often a temporary nuisance, it is important to pay attention to your symptoms. For mild cases, rest and at-home remedies are typically effective. However, if you experience more severe or persistent symptoms such as eye pain, vision changes, or thick discharge, it's wise to consult a doctor to rule out more serious conditions. An excellent resource for general eye health information is provided by the National Eye Institute.
