Swelling under one eye usually occurs due to a localized issue affecting the delicate tissues around the eye. Common causes include allergies, fluid retention, sinus congestion, insect bites, minor injuries, or irritation from rubbing the eye. Blocked tear ducts or infections such as conjunctivitis can also lead to puffiness beneath one eye.
Unlike swelling that affects both eyes, one-sided under-eye swelling often points to inflammation or irritation on that specific side of the face. In some cases, dental problems or sinus infections can cause pressure and swelling beneath a single eye. Identifying associated symptoms such as redness, pain, or discharge helps determine the underlying cause.
For sudden, painful, or worsening swelling under one eye, visiting an emergency room in Waxahachie can help determine the cause and ensure proper treatment.
Causes of Swelling Under One Eye
Swelling under one eye can be concerning because it often appears suddenly and affects only one side of the face. Unlike general facial puffiness, one-sided under-eye swelling is usually caused by localized factors rather than whole-body conditions. Identifying the cause helps determine whether the swelling is temporary or needs medical attention.
If swelling is sudden, painful, or persistent, you may want to search for an emergency room near me to ensure timely evaluation.
Allergic Reactions
Allergies are one of the most common reasons for swelling under one eye. Exposure to allergens such as pollen, dust, pet dander, or certain cosmetics can trigger inflammation in the sensitive under-eye area.
- Itching, redness, or watering of the eye
- Puffiness may worsen after rubbing
- Usually improves with antihistamines or avoiding triggers
Fluid Retention
Fluid can accumulate under one eye due to sleeping position, high salt intake, or dehydration. This type of swelling is often more noticeable in the morning.
- Puffiness without redness or pain
- May worsen after salty meals or poor sleep
- Often improves with hydration and elevation
Sinus Infection or Congestion
Sinus pressure and inflammation can cause swelling beneath one eye, especially if the affected sinus is located on one side of the face.
- Facial pressure or pain
- Nasal congestion or headache
- Swelling may feel tender to touch
Insect Bite or Local Irritation
A mosquito bite, sting, or contact with an irritant can cause localized swelling under one eye due to an inflammatory reaction.
- Sudden swelling on one side
- Mild itching or redness
- Usually resolves within a day or two
Eye Infection (Conjunctivitis or Cellulitis)
Infections around the eye can cause noticeable swelling, often accompanied by redness, warmth, or discharge.
- Pain, redness, or crusting
- Sensitivity to light
- Requires medical evaluation if symptoms worsen
Injury or Trauma
Even minor injuries to the face or eye area can cause swelling due to bruising or tissue inflammation.
- Swelling may appear hours after injury
- Discoloration or tenderness may develop
- Cold compresses often help reduce swelling
Blocked Tear Duct
A blocked tear duct can cause fluid buildup and swelling under one eye, especially near the inner corner.
- Watery eyes or discharge
- Mild pressure or discomfort
- More common in infants but can affect adults
When to Seek Medical Help
While minor swelling under one eye often resolves on its own, medical evaluation is recommended if you notice:
- Sudden onset or rapidly worsening swelling
- Severe pain or tenderness around the eye
- Vision changes such as blurriness, double vision, or difficulty seeing
- Redness, warmth, or fever, which may indicate infection
- Persistent swelling lasting several days without improvement
Healthcare providers may perform a physical examination, imaging, or lab tests to identify the underlying cause and recommend appropriate treatment.
Altus Emergency Care Key Takeaways
- Swelling under one eye is often caused by allergies, infections, injuries, fluid retention, or eye conditions.
- Localized irritation or systemic issues can trigger puffiness, but only one eye being affected usually points to a local cause.
- Self-care measures like cold compresses, reducing salt intake, avoiding rubbing, and managing allergies can relieve mild swelling.
- Persistent, painful, or vision-affecting swelling requires professional evaluation to rule out serious conditions.
- Recognizing the warning signs early helps prevent complications and ensures timely treatment.