Overview
The skin of the eyelid is a fraction of a millimetre thick and sits over loose tissue with a rich blood supply, so it takes up fluid faster and more visibly than skin anywhere else. That is why a salty dinner, a bad night or a few tears show up on the lids first.
The distinction that matters is puffiness versus true swelling. Soft, symmetrical, painless puffiness that eases through the morning is fluid. A hot, red, tender or one-sided swelling is inflammation or infection, and the speed at which it developed is the most useful thing to report.
What are the common symptoms?
- Soft puffiness of both lids, worst on waking
- Itchy, swollen lids with watering (allergy)
- A tender red lump at the lash line or in the lid
- Hot, spreading redness with fever
- Swelling that pushes the eye forward or limits its movement
What causes it, and who is at risk?
Everyday causes: fluid retention overnight, salt, alcohol, crying, lack of sleep, and the fat pads that gradually prolapse forward with age to make permanent under-eye bags.
Medical causes: allergic reactions to pollen, cosmetics or insect bites; styes and chalazia; blepharitis; conjunctivitis; blocked tear ducts; thyroid eye disease, which pushes the eye forward and retracts the lid; and kidney or heart problems, which swell both eyes symmetrically. Preseptal and orbital cellulitis are the dangerous end.
How is it treated?
Cool compresses, sleeping with the head slightly raised, less salt and alcohol, and time handle the ordinary version. Allergic swelling responds quickly to antihistamines and cool compresses.
A stye or chalazion is treated with warm compresses and lid massage, and a persistent chalazion can be drained in the office. Cellulitis needs antibiotics urgently. Long-standing fat-pad bags are a cosmetic surgical question rather than a medical one, and thyroid eye disease is managed jointly with an endocrinologist.
When to get seen quickly
Swelling with fever, spreading redness across the cheek or brow, pain on moving the eye, double vision, or a bulging eye is an emergency — orbital cellulitis can spread behind the eye within hours. Sudden swelling with breathing difficulty needs emergency care immediately.
This page is general information, not a diagnosis. Only an eye care professional who has examined you can tell you what is actually going on.