When the skin tells us about scabies

A clear guide without alarmism in dogs and cats

Scabies is one of the oldest and best-described parasitic skin diseases in veterinary medicine. Despite this, it remains a frequent cause for consultation and, above all, concern among pet owners, as it is immediately associated with intense itching, visible lesions and fear of contagion. However, it is important to start with a key idea: not all types of scabies are the same, not all are contagious, and not all have the same impact on health.

From a medical point of view, scabies is a skin disease caused by microscopic mites, arthropods that live on the skin or its appendages. European epidemiological studies estimate that between 5 and 10% of canine dermatological consultations are directly or indirectly related to mite infestations, with sarcoptic mange and demodicosis being the most commonly diagnosed in dogs, while in cats, notoedric mange clearly predominates in animals without regular health checks.

The severity of the clinical picture depends not only on the number of mites, but also on the host’s immune response. Therefore, two animals with the same infestation may present radically different symptoms. In clinical practice, it has been observed that owners tend to minimise the early signs, when in fact early diagnosis significantly reduces the duration of treatment and the risk of secondary complications, such as deep bacterial infections or chronic dermatitis.

Sarcoptic mange: relentless itching

Sarcoptic mange, caused by Sarcoptes scabiei, is one of the most aggressive forms from a clinical point of view. Various clinical studies have shown that more than 90% of affected dogs experience intense itching from the early stages, and that in approximately 7 out of 10 cases, this itching is described by owners as continuous or unbearable, with worsening at night.

Interesting fact: the complete life cycle of the mite is around 3 weeks

In sarcoptic mange, the mite is described as going from egg to adult in approximately 3 weeks, and the signs may take time to appear because the animal becomes sensitised over time. This helps to explain “sudden” outbreaks after previous contact.

The mite burrows into the epidermis, triggering a very pronounced inflammatory and allergic response. This reaction explains why, even with a low parasite load, symptoms can be extremely severe. Lesions are mainly located in areas with little hair—ears, elbows, abdomen, and chest—and progress to scabs, extensive alopecia, and skin thickening if not treated in time.

From a public health perspective, sarcoptic mange is relevant because it is a zoonosis. Observational studies indicate that up to 30% of humans living with affected animals may develop transient skin lesions when the animal has not yet been treated. In these cases, Sarcoptes scabiei var. canis is unable to adapt or complete its life cycle on human skin, so it does not reproduce and ends up dying within a few days. However, during this time it can cause intense itching, skin rashes and uncomfortable inflammatory lesions due to the skin’s immune reaction to the mite. These lesions usually resolve spontaneously after the animal source has been removed, which reinforces the importance of starting treatment without delay and continuing it until the end, even when the animal shows clinical improvement in the first few days.

Useful scientific note for the home: outside the host, they live for a short time… but not zero

A classic experimental study showed that Sarcoptes scabiei can survive outside the host for around 24–36 hours at room temperature, although cold and humid conditions prolong survival. This is perfect for recommending reasonable hygiene without obsession: “cleanliness yes, panic no”.

In practice, diagnosis can be complex, as skin scrapings may be negative. Several clinical studies have shown that only about 30% of skin scrapings are positive, even in animals that are clearly infested. This is because Sarcoptes scabiei is located in very deep layers of the epidermis, where it burrows tunnels for protection, requiring sufficiently deep scrapings—sometimes uncomfortable for the animal—to capture the mites. For this reason, response to treatment is part of the usual diagnostic approach, and strict adherence to the prescribed regimen is essential to avoid relapses and false therapeutic failures.

Notoedric mange: the great forgotten disease in cats

Notoedric mange, caused by Notoedres cati, is much less well known to owners, but it remains a relevant pathology in cats, especially in animals from the street, colonies or shelters. Studies carried out in feline populations without health control show prevalences ranging from 3 to 15%, with higher peaks in high-density environments.

This form of mange is especially common in young kittens, where the parasite load can be high from an early age. In these animals, stress, early weaning or an immature immune system favour the multiplication of the mite, which explains why notoedric mange is much more common and more severe in young, orphaned or recently weaned animals than in healthy adult cats.  In addition, factors such as stress favour the multiplication of the mite and explain the particular severity of the condition in young animals.

“The ear test” with real figures (pinnal-pedal reflex)

In a classic study involving 588 dogs with skin disease, the otopodal or pinnal-pedal reflex (scratching of the hind limb when rubbing the edge of the ear) showed a sensitivity of 81.8% and a specificity of 93.8% for sarcoptic mange. Translated: if the reflex is negative, it greatly reduces the probability; if it is positive, it is a strong indicator, but does not confirm 100%. However, the definitive diagnosis is based on direct visualisation of the mite under a microscope.

At the Eurovet Veterinary Clinic, one of the most frequent errors we continue to observe is the failure to systematically perform microscopic observation of ear samples in cases of feline otitis. This omission can lead to confusion between notoedric mange and inflammatory otitis and to the initiation of corticosteroid treatments.

These drugs produce rapid and misleading improvement by suppressing itching, but at the same time they depress local immunity, promoting more intense proliferation of the mite and more severe relapses. A recent example is the case of Milo, a young cat treated for weeks for recurrent otitis, who presented with ear and facial scabs; microscopy identified Notoedres cati. After discontinuing corticosteroids and initiating appropriate antiparasitic treatment, the outcome was favourable.

This type of situation reminds us that looking through a microscope remains a key diagnostic step, especially in young cats, and that omitting it can lead to initially simple pathologies becoming chronic.

Clinically, it is characterised by intense facial pruritus, accompanied by thick scabs and progressive thickening of the skin. In advanced stages, the condition can spread from the head to the neck and forelimbs. Diagnostic delay is common, as the initial lesions are confused with traumatic wounds or allergic dermatitis, when in fact progression without treatment can lead to weight loss, apathy and general deterioration, especially in young or debilitated cats.

Real clinical case 🐾

It is not uncommon for a single kitten with lesions to be brought to the clinic, when in fact the entire litter is infested, even though the siblings are not yet scratching. In these cases, treating only the “most affected” animal often leads to repeated reinfestations, so the correct approach is always a comprehensive one.

Demodectic mange: when the problem is not the mite, but the immune system

Demodectic mange, or demodicosis, represents a different paradigm. Mites of the genus Demodex are part of the normal skin microbiota, and microscopic studies have shown their presence in more than 80% of healthy dogs without clinical disease (HERE D1).

The pathology appears when an immune imbalance occurs. In young dogs, the localised form is the most common and, according to longitudinal studies, up to 90% of these cases resolve spontaneously, which is why controlled clinical observation is often preferable to unnecessary aggressive treatments (HERE D2).

In contrast, the generalised form is much more serious. It is estimated that between 30% and 50% of dogs with generalised demodicosis have secondary bacterial infections, which complicates the condition and prolongs treatment. When the disease first appears in an adult animal, the possibility of an underlying condition that is weakening the immune system, such as endocrine disorders or prolonged immunosuppressive treatments, should always be considered.

Veterinary history fact 📚

For decades, generalised demodectic mange was considered a difficult disease to control and with a poor prognosis. The arrival of new systemic antiparasitic molecules has revolutionised treatment, dramatically improving the quality of life and prognosis of these patients.

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