The brain misinterprets what the nose encounters
En el rastro silencioso que el COVID-19 deja tras de sí, uno de cada cinco sobrevivientes descubre que el mundo ya no huele igual. Médicos del Hospital Guillermo Almenara de EsSalud en Perú advierten que el virus no solo compromete los pulmones, sino que alcanza el sistema nervioso y altera de manera duradera las células responsables del olfato y el gusto. Lo que para muchos parecía un síntoma pasajero se revela, meses después, como una secuela que exige atención médica y vigilancia sostenida. En la historia de esta pandemia, el olfato perdido se convierte en un recordatorio de que la recuperación no siempre es completa ni inmediata.
- Casi el 20% de quienes superan el COVID-19 enfrentan trastornos olfativos persistentes que van desde la reducción parcial del olfato hasta su pérdida total o su distorsión inquietante.
- La parosmia —la condición más desconcertante— hace que el cerebro malinterprete los olores, generando confusiones sensoriales o incluso alucinaciones olfativas que alteran profundamente la vida cotidiana.
- El virus ataca directamente las células olfativas y gustativas al penetrar en el sistema nervioso central y periférico, dejando un daño neurológico que puede prolongarse mucho más allá de la infección aguda.
- El Hospital Guillermo Almenara ha registrado un flujo constante de pacientes con estas secuelas, lo que llevó a los especialistas a emitir una alerta pública ante la magnitud del fenómeno.
- La endoscopia nasal se posiciona como herramienta diagnóstica clave para descartar obstrucciones físicas e identificar el origen neurológico del trastorno, abriendo paso a un tratamiento oportuno.
- Los médicos insisten en que la detección temprana de síntomas persistentes puede reducir significativamente las complicaciones, convirtiendo la vigilancia post-infección en un acto de cuidado esencial.
Uno de cada cinco sobrevivientes del COVID-19 arrastra, semanas o meses después de superar la infección, una alteración en su sentido del olfato. Así lo advierten los especialistas del Hospital Guillermo Almenara, perteneciente al sistema de salud EsSalud en Perú, quienes han seguido de cerca la evolución de pacientes en la etapa post-COVID.
Omar González, otorrinolaringólogo del hospital, explica que el virus va más allá del daño pulmonar: penetra en el sistema nervioso —tanto central como periférico— y ataca específicamente las células encargadas del olfato y el gusto. Este daño puede manifestarse desde los primeros días de enfermedad y persistir mucho después de que la fiebre y la tos desaparecen.
Los trastornos olfativos adoptan distintas formas. La hiposmia reduce la intensidad de los olores; la anosmia los elimina por completo. Pero es la parosmia la que resulta más desconcertante: el cerebro distorsiona las señales que recibe, haciendo que una persona perciba olores que no existen o confunda unos con otros. La señal sensorial se pierde en algún punto entre la nariz y el cerebro.
Ante estos síntomas, el primer paso clínico es una endoscopia nasal para descartar causas físicas y confirmar el origen neurológico del problema. En los últimos meses, el hospital ha atendido a numerosos pacientes con estas quejas, entre ellos un joven que, dos meses después de recuperarse, seguía sin reconocer los olores de siempre.
El mensaje de González equilibra la precaución con la esperanza: prevenir la infección sigue siendo la mejor estrategia, pero quienes ya la padecieron deben prestar atención a los síntomas que no ceden. Detectarlos a tiempo marca la diferencia entre una complicación menor y una secuela prolongada.
Nearly one in five people who recover from COVID-19 are left with lingering problems in how they smell. That's the warning from doctors at Hospital Guillermo Almenara, part of Peru's EsSalud health system, who have been tracking what happens to patients in the months after infection clears.
Omar González, an ear, nose, and throat specialist at the hospital, explained that the virus doesn't just damage the lungs. It also reaches deeper into the nervous system—both the central and peripheral networks—and specifically attacks the cells responsible for smell and taste. The damage can show up early in illness and stick around long after the acute infection passes.
The olfactory problems take several forms, each one distinct. Hyposmia is a dulling of the sense—smells become faint, harder to detect. Anosmia is total loss; the person cannot smell anything at all. But there's a third condition, parosmia, that's stranger still. In parosmia, the brain misinterprets what the nose encounters. A person might smell something that isn't there, or confuse one smell for another entirely. The sensory signal gets scrambled somewhere between the nose and the brain.
When a patient arrives at the hospital reporting these kinds of problems, González said the first step is a nasal endoscopy—a thin camera threaded through the nose to look for any physical blockage or obstruction that might explain the symptoms. This rules out simpler causes and points toward the neurological damage the virus leaves behind.
In recent months, the Almenara hospital has seen a steady stream of former COVID patients with these complaints. González described one young man who had recovered from the infection two months earlier but found his sense of smell fundamentally altered. He was not alone. The pattern is clear enough that the hospital felt obliged to alert the public.
The message from González carries both caution and hope. Prevention remains the strongest tool—avoiding infection in the first place is always better than managing what comes after. But for those who do get sick, vigilance matters. Paying attention to symptoms that linger, that don't fade with the fever and cough, can make the difference between a problem caught early and one that compounds over time. The sooner a diagnosis is made, the sooner treatment can begin, and the fewer complications are likely to follow.
Citações Notáveis
The virus causes respiratory alterations, but also affects the central and peripheral nervous systems, including olfactory and gustatory cells.— Dr. Omar González, otorhinolaryngologist at Hospital Guillermo Almenara
The most important thing is always to prevent infection, but if we do get sick, we must watch for persistent symptoms—early diagnosis means fewer complications later.— Dr. Omar González
A Conversa do Hearth Outra perspectiva sobre a história
So one in five survivors—that's a significant number. Are these people aware it's happening, or does it creep up on them?
It can appear right alongside the initial illness, but that's the tricky part. People are so focused on breathing, on fever, that a dulled sense of smell might not register as important. Then weeks later, they realize it hasn't come back.
And parosmia—the hallucination part—that sounds genuinely disorienting. What does that feel like from the patient's perspective?
Imagine smelling something foul when nothing is there, or tasting your coffee and your brain tells you it's something completely different. It's not just an inconvenience. It affects how you eat, how you experience the world. Some people lose weight because food becomes unappetizing.
The doctor mentions an endoscopy as the first step. What's he actually looking for?
He's ruling out the obvious—a polyp, inflammation, something physical blocking the passage. Once he knows the nose itself is clear, he knows the problem is neurological. That's when the real work begins.
Is there treatment, or is this something people just have to live with?
The article doesn't specify the treatment itself, but the point González makes is clear: early detection matters. The sooner you know what's happening, the more options exist to manage it.
Why does this matter enough to warn the public now, in April 2021?
Because people are still recovering. The hospital is seeing it happen regularly. If survivors know to watch for it, they can seek help instead of assuming their sense of smell will simply return on its own.