Reduced nasal airflow and odor identification in vernal keratoconjunctivitis (VKC): beyond the ocular surface

For decades, doctors have viewed vernal keratoconjunctivitis as a disease that lives entirely within the eye. It is a chronic, itchy inflammation that strikes children, usually boys, with a vengeance during the spring and summer. The condition causes intense itching, sensitivity to light, and a thick, mucus-like discharge. In severe cases, it can damage the cornea and threaten vision. Because the symptoms are so visibly centered on the eyes, the medical community has traditionally treated it as an isolated ocular problem, even though many of these children also suffer from other allergic conditions like hay fever. This narrow focus has left a gap in understanding: is the inflammation truly confined to the eye, or does it ripple outward to affect the rest of the upper airway, including the nose and the sense of smell?

A new study from researchers in Rome suggests that the problem may be much broader than previously thought. By looking closely at a group of children with this eye condition, the team discovered that many of them also struggle with breathing through their noses and identifying common smells. Crucially, these issues appeared to be linked to the eye disease itself, not just to the presence of general allergies. The findings challenge the idea that vernal keratoconjunctivitis is strictly an eye condition, hinting instead that it might be part of a wider inflammatory process affecting the entire upper airway.

To investigate this, the researchers gathered eighty children and teenagers at a pediatric allergy clinic in Rome. Fifty-five of these participants had a confirmed diagnosis of vernal keratoconjunctivitis, while the remaining twenty-five served as a control group without the eye disease. The team was careful to distinguish between the eye disease and general allergic sensitization. They defined a child as having "atopy," or a tendency toward allergies, only if they had both a positive reaction to allergy skin tests and a history of symptoms consistent with hay fever. This distinction was vital because the researchers wanted to know if the nose and smell problems were caused by the eye disease itself, or simply because these children happened to have other allergies.

The testing process was thorough and objective. First, the team measured how easily air could flow through each child's nose using a device called active anterior rhinomanometry. This tool measures the relationship between air pressure and airflow, giving a clear picture of how open or blocked the nasal passages are. Next, for the children old enough to participate, the researchers tested their sense of smell. They used a specialized kit containing twelve familiar scents, such as apple, coffee, and lemon. The children were asked to sniff each scent and identify it from a list of four options. This method provided a concrete score for their ability to recognize odors, moving beyond simple guesses to a measurable performance.

The results revealed a striking pattern. Among the children with the eye disease, more than forty percent had abnormal nasal airflow, meaning their noses were significantly more blocked than expected. In contrast, only sixteen percent of the children without the eye disease showed similar blockages. The difference was even more pronounced when it came to smell. More than half of the children with the eye condition struggled to identify the scents correctly, compared to just twenty-two percent of the control group. These numbers suggested that the children with the eye disease were facing a dual challenge: their noses were physically harder to breathe through, and their ability to recognize smells was diminished.

The researchers then asked a critical question: could these results simply be explained by the fact that many of these children also had allergies? To answer this, they used statistical models to separate the effects of the eye disease from the effects of general allergies. They found that even after accounting for whether a child had hay fever or other allergic sensitivities, the link between the eye disease and the nasal problems persisted. Children with the eye condition were still about four times more likely to have blocked noses and reduced smell function than those without it, regardless of their allergy status. However, the researchers caution that while these associations are statistically significant, the estimates have wide confidence intervals, meaning the exact strength of the link cannot be precisely determined. The term "independent predictor" used here denotes an association that remains after adjustment, but it does not imply that the eye disease directly causes the nasal issues; rather, the findings are considered exploratory and require further confirmation.

The study does not claim to have solved the mystery of why this happens, but it offers a compelling new direction for understanding the disease. The researchers suggest that the eye and the nose may be connected through shared biological pathways, perhaps involving the immune system or the nerves that control the mucous membranes. It is possible that the same inflammatory forces attacking the eye are also affecting the nasal lining, even if the child does not have a classic case of hay fever. The study explicitly notes that it does not establish direct causation, showing instead that the eye disease is a significant factor associated with these nasal issues, distinct from the general allergic response.

However, the researchers are careful not to overstate their findings. They acknowledge that their study was relatively small and that the results need to be confirmed by larger, long-term studies. They do not yet know if these nasal problems get worse when the eye symptoms flare up, or if they improve when the eye condition is treated. They also cannot say for sure if this pattern applies to all children with the disease or just a specific subgroup. What they have established is that the nose and the sense of smell are frequently involved in a way that has been overlooked.

This shift in perspective has practical implications for how doctors might care for these children. Currently, treatment focuses almost entirely on the eyes to prevent vision loss. The study suggests that doctors should also ask about nasal congestion and changes in the sense of smell when evaluating a child with this condition. If a child is struggling to breathe through their nose or cannot identify familiar scents, these symptoms should not be dismissed as unrelated. They may be a direct part of the disease process. By recognizing this broader involvement, clinicians can offer a more complete assessment and potentially better care, treating the child as a whole rather than just focusing on the eyes. The work opens a door to seeing vernal keratoconjunctivitis not as an isolated eye trouble, but as a condition that can reach further into the body than anyone realized.