Dog Health

Click for dog health information

Read more

Cat Health

Click for cat health information

Read more


Click for rabbit health information

Read more

Flea Allergic Dermatitis

Fungal Infections


Flea Allergic Dermatitis

What are the signs of flea allergic dermatitis?

The most consistent signs of dermatitis are scratching and reddening of the skin. Apart from this the signs will depend somewhat on the severity and cause.

There may be scabs, sores, crusting, pustules, flaking, oily discharge, discharge, thickening, colour changes (usually darker or redder), hair loss over the back and in extreme cases bleeding. The presence of live fleas or flea dirt (black specks that turn red if wet) usually indicates a flea allergic dermatitis.

If puppies or kittens are exposed to fleas very early on in life, they are more likely to become sufferers of flea allergic dermatitis later on in their lives.

For this reason, it is vital to treat kittens, puppies and their mothers as early on as possible. Individual flea allergic pets have different thresholds above which they show clinical signs.

The threshold could be hundreds of biting fleas causing intense biting and scratching in your pet or just one flea which you may never see. Pets are allergic to the saliva of the flea.

A flea allergy could kill your pet. It could lead to so much biting and scratching if they are badly allergic which causes a secondary skin infection with what we call a deep pyoderma where the normal skin bacteria multiplies and causes a deep infection. This can lead to the bacteria entering the bloodstream and poisoning it.


The obvious first line of treatment is a veterinary product to kill the live fleas. A flea product such as a spray for the home should also be used as well as a product to sterilise the life cycle of the flea if your dog suffers from flea allergic dermatitis.

We then treat the secondary infection with antibiotics and the itching with a course of anti-inflammatories. Medicated shampoos may also help to soothe your pet's irritated skin.


Fungal infections


Fungal infections in dogs and puppies include skin infections such as ringworm and deep fungal infections affecting the skin.

  • Aspergillosis

Aspergillosis is a fungal infection that develops in the nose and sinuses of dogs. Infections with this fungus show very characteristic symptoms including nasal discharge.

Aspergillosis can be difficult to diagnose and treat. Early detection and treatment are very important for controlling this potentially damaging disease.

Aspergillus is a very common fungus that is found throughout the environment. Most animals and people will come into contact with this fungus at some point in their lives, however, most animals do not develop infections.

Most infections occur in animals that have a poor or deficient immune system, a prior sinus infection or in animals that have been on prolonged antibiotic therapy.

In addition, animals that are undergoing chemotherapy or have a pre-existing disease such as diabetes mellitus are more prone to developing aspergillosis. However, Aspergillus can infect healthy animals with a normal immune system as well.

Aspergillus is not transmitted between animals or humans; infections come from the environment.

However, infected animals should still be handled with care and owners of an infected animal who wear contact lenses should be aware that aspergillosis can cause serious eye disease.

If you ever notice ulcerations on your pet's nose or a large amount of nasal discharge make sure to have your pet examined by a veterinarian as soon as possible.

  • Malassezia (yeast) infections

Malassezia pachydermatis is a yeast that is commonly found on the skin of most dogs. The presence of yeast normally causes few problems, however, in some cases, Malassezia can grow and reproduce in abnormal numbers.

Any hereditary or infectious disease that weakens the skin's immune system can allow a Malassezia infection to begin.

Animals that have an underlying condition such as a bacterial infection, allergy or seborrhea can have irritated skin that is then susceptible to becoming infected with Malassezia.

Some animals, particularly Basset Hounds, West Highland White Terriers and Bulldogs, are particularly prone to Malassezia.

Treatment can be approached in several different ways. For a long-term solution to the problem the underlying condition must be properly treated, whether it is a bacterial infection, allergy, or seborrhea.

To provide an inhospitable environment for Malassezia, lipids on the skin need to be removed. Specific shampoos that contain benzoyl peroxide are used.

For dogs with more severe cases, or in those that are resistant to shampoos and topical treatment or oral ketoconazole can be administered for several weeks.

A response is generally seen within 1-2 weeks, however, therapy needs to continue for an additional 3-5 weeks. Antifungal drugs are very effective, but because of their potentially toxic side effects and expense, they should only be used under direct veterinary supervision.

  • Ringworm

Ringworm is a well known fungus that can infect dogs, cats and humans. Many people have either had or known someone that has had a ringworm infection.

There are several different forms of the fungus which can infect either you or your pet.

The diagnosis and treatment is fairly straightforward for all species, however, some species affecting dogs can be much more difficult. Every pet owner should be aware of the signs, transmission, and treatment of ringworm.

Ringworm can be transmitted by direct contact with an infected animal, or contact with an item that is contaminated with the spores.

The spore can be on infected grooming equipment or brushes, in a contaminated boarding facility or kennel, or in the environment where an infected animal has visited.

Fortunately, most healthy adult dogs have some resistance to ringworm and never develop symptoms from the fungus. Young dogs are most often infected.

Dogs with a suppressed immune system from other diseases or overuse of steroids are also more susceptible to contracting the disease.

A popular but not completely accurate way to diagnose the disease is through the use of a specialised black light called a Wood's lamp. The best and most accurate way to identify a ringworm infection is by collecting scales and crust from the skin and coat and performing a culture.

There are special culture mediums designed specifically for identifying ringworm infections. Your veterinarian can easily perform this routine culture.

Most small, isolated lesions on healthy dogs and puppies will heal on their own within 4 months. In more severe cases, several different treatments are used. For isolated lesions, the area around the lesion should be thoroughly clipped down close to the skin.

Care should be taken when clipping not to irritate the skin, as this may promote spreading of the infection. The lesions can then be treated topically twice a day with an antifungal medication.