Eye pain during a cold, flu, or other respiratory illness is a common and often alarming symptom. This discomfort, which can range from a dull ache to sharp pressure, is rarely a primary eye problem itself. Instead, the pain is typically a consequence of the body’s generalized response to infection, primarily involving inflammation and pressure changes. Understanding the origins of this discomfort, whether it is a referred sensation or a systemic effect, can offer reassurance during illness.
Referred Pain from Sinus Pressure
The inflammation of the paranasal sinuses is a frequent cause of discomfort around the eyes during illness. These air-filled cavities are positioned directly above, between, and behind the eyes. Infection triggers the lining of the sinuses to swell, leading to a buildup of fluid and mucus. This internal pressure is then transmitted to the surrounding areas, including the eye sockets, resulting in referred pain.
The pain is often described as a deep, dull ache or a sensation of fullness behind the eyes. This discomfort may feel more intense when a person bends over, coughs, or moves their head suddenly, as these actions increase pressure within the congested cavities. When the ethmoid sinuses are affected, the pain is felt acutely behind the bridge of the nose and around the inner corners of the eyes.
Systemic Inflammation and Body Aches
Beyond localized pressure, the body’s overall inflammatory response to infection contributes to eye discomfort. The immune system releases chemical messengers that lead to symptoms like fever and muscle aches (myalgia). The small extraocular muscles, which control eye movement, can also be affected by this generalized soreness. Moving the eyes may cause a noticeable, painful ache due to inflammation in these muscle fibers.
Systemic inflammation and fever can lower the pain threshold, making the eyes sensitive to light (photophobia). This is a common complaint during illnesses that cause headaches and fever. The eyes can also become dry and irritated, a condition exacerbated by dehydration that frequently accompanies sickness. Dryness leads to a burning or gritty feeling perceived as pain.
Direct Eye Infections
Eye pain can also be caused by a direct infection of the eye occurring concurrently with a respiratory illness. The most common primary infection is conjunctivitis, or pink eye, which is inflammation of the clear membrane covering the eye and inner eyelid. Viral conjunctivitis is frequently caused by the same viruses responsible for the common cold.
This infection typically begins in one eye and may spread to the other, presenting with symptoms distinct from referred pain. Indicators include noticeable redness, a gritty sensation, and a clear, watery discharge. A secondary bacterial infection may also occur, characterized by a thick, yellow or greenish discharge that causes the eyelids to stick together upon waking. These direct infections cause genuine ocular pain and require separate management.
When Eye Pain Signals a Serious Problem
Most eye pain during an illness resolves as the underlying condition improves, but certain signs signal a more serious medical issue. Severe, unrelenting pain that prevents sleep or is accompanied by neurological symptoms requires immediate medical attention. A significant red flag is any sudden change in vision, such as blurriness, double vision, or abrupt loss of sight. These symptoms may indicate a deeper problem affecting the optic nerve or cornea.
Pain accompanied by nausea or vomiting, especially if the eye is intensely red, can signal acute angle-closure glaucoma, a condition where pressure inside the eye rises rapidly. Other signs requiring urgent evaluation include an inability to move the eye normally, pain with eye movement, or seeing halos around lights. These symptoms differentiate serious conditions, such as orbital cellulitis or uveitis, from the simple aches associated with a cold or flu.