The blind spot in clinical history-taking

There are some questions that do not appear in protocols or forms, and yet have the potential to entirely change how a patient’s clinical presentation is interpreted and, sometimes, to point towards its cause.

One of them is: “Do you live with, or have regular contact with, animals?”

In 52% of Spanish households, the answer will be yes. Moreover, nine out of ten people consider their pets members of the family, which means they live in close proximity.

Yet, more often than not, this information does not become part of the patient’s clinical record, and we casually cast a shadow over highly relevant details—not because the patient conceals them, but because nobody asks.

We have developed a medical system that is extraordinarily effective at diagnosing and treating disease, but surprisingly limited in its understanding of the context in which a pathological process arises. This can completely change the clinical interpretation of the patient, their response to treatment or their adherence to the recommendations given.

For example, a patient with scabies may follow all the hygiene measures correctly and take all the prescribed medication. But if nobody thinks to ask whether they live with a dog or cat, and nobody advises them to take the animal to a vet to be examined and given the appropriate preventive or curative treatment, then, while there is an outbreak in the household, the animal will remain a permanent reservoir and source of reinfection.

We have become accustomed to treating patients in an overly simplified, abstract version of reality: as organisms with symptoms, stripped of their surroundings, everyday routines and relationships.

But life unfolds in complex domestic ecosystems where people, animals, plants, habits, emotions and biological risks coexist—risks that recognise neither administrative boundaries nor outdated practices. We know that human health does not exist in isolation, yet we continue to act as if it does, perpetuating a clinical blind spot that serves no one.

Although still limited, the scientific literature is fairly clear on this point. Healthcare professionals do not generally ask routinely about living with animals. It is not a deliberate omission or an act of negligence. It is simply a structural absence. It is not part of the protocols, the training or the clinical culture. And this reality urgently needs to change.

The study by Hodgson et al.  (2017), based on surveys of primary care professionals, is particularly illustrative. Before a training intervention, the presence of animals in the home was not part of routine history-taking. After it was introduced, clinicians reported significant improvements in communication with patients and in the quality of care. Other subsequent studies support this finding: there is a theoretical awareness of the impact animals can have on health, but no structured integration of this awareness into clinical practice.

“Healthcare professionals do not generally ask routinely about living with animals.”

When this question is introduced, it changes the clinical interpretation in quite a few cases. This raises an unavoidable question: “What are we failing to see because we do not ask?”.

In an ageing society, with rising numbers of immunocompromised and chronically ill patients, living with animals is common because of the companionship and benefits they offer to people’s well-being. However, it can sometimes also involve clinical risks.

Relationships with animals have a proven positive impact on physical and mental health: they reduce stress, provide companionship and lift people’s mood; encourage physical activity, such as going for two walks a day; help structure routines; and, in certain contexts, act as a genuine source of emotional support. Yet in clinical practice, this dimension is not measured, incorporated into decision-making or considered as part of an overall assessment of the patient and their well-being. And yet that bond explains a great deal.

It explains why some patients delay important medical decisions. It explains apparently irrational reluctance to be admitted to hospital. It explains defective adherence to treatment. It is not always a lack of understanding of their clinical condition, unwillingness or rejection of the recommended course of action. Sometimes it is something as simple as not knowing what will happen to their animal if they are admitted to hospital, if their routine changes or if they lose their independence. But if no one asks, the issue is not understood and may be misinterpreted.

There are situations in which this omission takes on an even more sensitive dimension. In contexts of social vulnerability or violence, animals can become silent indicators of the problem. Harm or threats directed at an animal can be a way of controlling a person. And yet this aspect is rarely explored in consultations. —not because it is irrelevant, but because it does not form part of the framework through which day-to-day practice is approached.

What is surprising is that the animal’s health status, living conditions, health and preventive hygiene measures, and cross-species risks are not assessed either—not even for patients in high-risk groups.

In medical consultations, clinicians encounter infections with no clear source, recurrent gastrointestinal symptoms and colonisation by multidrug-resistant bacteria in patients with no hospital exposure. Yet they rarely ask whether the patient lives with an animal, whether it has recently suffered from an illness or what it eats. Raw diets prepared in the family kitchen considerably increase the risk of zoonoses.

This is not a lack of knowledge; it is a lack of integration.

For decades, we have built highly specialised healthcare systems that are effective within their respective fields, but organised in silos. Human medicine, veterinary medicine, public health, food safety … each has advanced along its own path, with few genuine points of connection. The result is fragmentation that makes it harder to understand problems that are, by nature, interdependent.

We know that most emerging diseases are zoonotic. We know that environmental, social and animal factors affect human health. We know that the current model is inadequate for the challenges of the 21st century. And yet we continue asking questions as though nothing had changed. Meanwhile, we continue to lose relevant information in every consultation.

This is where the problem stops being clinical and becomes structural. The aim is not to complicate clinical practice, but to update it so that it meets this new need. Incorporating this dimension requires only one simple thing: asking questions.

They are not complex questions. They require neither technology nor artificial intelligence nor major investment.  What is needed is a broader view of the patient’s environment and, of course, the willingness to change the protocol.

This raises further questions: where to start, how to ask, what to ask about and for what purpose. Before more comprehensive training on this subject becomes available, one could start with the accompanying table, which I hope will provide a useful starting point.

And as you read through it, you’ll probably think: “How is it possible that we haven’t asked this before?”.

The question is not whether we should change the clinical history-taking process. The question is how much longer we can afford not to.

Perhaps it is not about making medicine more complex, but about making it less incomplete.

Table 1. Clinical history-taking checklist on living with animals

Source New Medical Economics nº 232, pp. 60-62.