Skin Problems in Dogs and Cats

Skin problems in dogs and cats can have many different causes. Pet owners often notice something is wrong when their animal scratches excessively, develops bald spots, shows bumps, or when parasites are visible in the coat. Below are the most common causes.

Parasites

Dogs and cats can suffer from various types of skin parasites.
Fleas, for example, are highly contagious. A single flea can lay up to 50 eggs per day, and as many as 80% of those end up in the environment - your home or garden. If an animal with fleas is nearby, your pet can easily pick them up.
Ticks are another common parasite. They usually do not cause itching but can be felt as small bumps, especially in areas such as the armpits, ears, or skin folds. A common misconception is that ticks are only found in forests; in reality, they are often present in tall grass or shrubs as well. Ticks can transmit diseases through their saliva. Although most of these diseases are mainly found in Southern Europe, they are increasingly being seen in the Netherlands.
Mites are harder to detect because they are microscopic. However, they often cause severe itching, as they burrow into the outer layer of the skin and feed on skin debris.

Allergies

Another major cause of skin problems is allergies. Allergies typically present as redness and itching of the skin. In severe cases, the skin can become damaged due to inflammation, allowing bacteria, fungi, and mites to develop. Treatment of a severely allergic animal may therefore involve multiple approaches: antibiotics, antifungal treatments, and medication to control the allergic reaction.

Animals are most commonly allergic to a type of meat. In about 80% of cases, this involves chicken, beef, or lamb. Even small traces or flavorings derived from these sources can trigger a strong reaction, sometimes up to 6 weeks after consumption. This makes it difficult to immediately identify the allergen. In properly formulated hypoallergenic pet food, no traces of these meats are present unless they are hydrolyzed (broken down into very small components). For managing allergies, it is always recommended to consult your veterinarian.

Dogs and cats can also develop contact allergies. This may include reactions to detergents used to wash their bedding, cleaning products used on floors, or shampoos containing fragrances or harsh chemicals. For allergic animals, it is important to carefully evaluate all products used in their environment and grooming routine. As a veterinarian, I recommend natural shampoos that do not contain harmful chemicals or (micro)plastics. Personally, I wouldn’t use such products on myself either - so I certainly wouldn’t on my beloved four-legged companion.

Lumps

Cysts

Animals can develop various types of lumps. Sometimes, cysts form after an injury or impact. These are cavities filled with fluid and are generally harmless unless they cause discomfort. Some cysts resolve on their own, while others become encapsulated by the body. A veterinarian can diagnose a cyst by inserting a needle and examining the fluid.

Abscesses

If a lump is punctured and contains pus, it is often an abscess. These are common in cats, especially those that go outdoors and fight. Before an abscess develops, animals may become lethargic, eat poorly or not at all, and develop a fever. Abscesses can also result from dental issues or a foreign object, such as a splinter, in the body.

Tumors

Pets can also develop tumors, which may be benign or malignant. To determine the type, a veterinarian may perform a fine needle aspirate biopsy (FNAB). This helps provide advice on whether the lump should be removed, how extensively, and whether it is likely to spread to other organs such as the lungs or abdomen.

Did you know that some tumors can be caused by UV radiation? Cats with white ears are particularly at risk of squamous cell carcinoma, a malignant tumor that may require ear amputation. Melanomas in dogs, cats, and horses can also be linked to sun exposure. That’s why it’s important to use a natural sunscreen specifically formulated for animals on sunny days.

The good news? A histiocytoma is a benign lump that often disappears on its own, especially in young animals.
Note: this is not the same as the papillomavirus, which causes wart-like growths around the mouth, eyes, or nose in young puppies. This condition also resolves spontaneously but is contagious to other young animals.

Hair Loss

Circular bald patches in dogs and cats may indicate ringworm, a fungal infection. This is best diagnosed by a veterinarian, who will collect hair and skin crusts from the area and perform a PCR dermatophyte test. If positive, antifungal medication is required.

Hair loss can also be hormonal, caused by conditions such as Cushing’s disease, diabetes, or thyroid disorders. A veterinarian can diagnose these through blood and urine tests. In such cases, other symptoms are often present, such as lethargy, increased thirst or urination, weight gain, or weight loss.

Trauma

Sometimes skin problems are simply caused by injuries, such as falls, bites, or sunburn. Animals can also get sunburned, especially in areas with little or no fur, such as the ears, belly, or regions with thin or light-colored coats.

Do you have questions about natural shampoos or sunscreen for your pet? Please let us know.