"This can then set up a vicious cycle of itching and scratching. The hot and humid climate in Hong Kong may increase the chance of both allergic reactions and secondary infections," the vet says.

Signs of allergies vary, but commonly affected areas include the feet, ears, armpits and belly. In some cases, the signs can be quite subtle - for example, a dog that is frequently seen licking or biting its feet, or has recurrent ear infections may have an underlying allergy.

Allergies can occur in any type of dog, but some breeds such as poodles, shih tzus, schnauzers, pugs and golden retrievers are more likely to develop skin problems. They can take a while to develop, but signs are frequently first observed in dogs aged six months to three years old.

According to Cable, there are several types of skin allergies in dogs: environmental, food, reactions to insect bites. "It's often difficult to determine the exact type of allergy based on just the signs, but it can be important in helping to eliminate or avoid the cause of the allergy."

An environmental allergy, also called atopy, is the most common cause and involves sensitivity to normal particles in the air. Common environmental allergens include dust mites, pollens and moulds, and signs may be more prevalent at certain times of the year, such as the start of summer.

Contact allergies tend to affect only the part of the animal that touches the allergen. Contact allergens may include carpet fibres or washing powders. Such allergens can often be reduced by changing cleaning products, or rinsing floors or clothing with water.

Insect bite allergies, especially those from flea bites, can become a big problem. "Some animals can react much more strongly to a flea bite, resulting in intense itching and irritation. For this reason, all dogs with itchy skin should be taking flea prevention," Cable says.

Food allergies make up about 10 to 20 per cent of skin allergy cases in dogs. "Food allergies can cause an upset stomach, loose stools and gastrointestinal irritation, but in many cases the only sign of food allergies is itchy skin," the vet says.

The most common allergies are to beef, wheat, dairy, eggs and chicken. "One of the best ways to help with food allergies is to cut out any snacks or treats, and monitor the response. This will need to be done for six to eight weeks in order to give time for the skin to adapt."

Treating these allergies can be difficult, Cable says, and in some cases can prove to be frustrating. "Many dogs do need to be treated for long periods, and it can be difficult to permanently cure allergies - instead, we aim to manage them."

The first step in allergy management is to determine what a pet is allergic to - a process that may involve skin tests or blood tests. In many cases, it is impossible to determine every allergen affecting a pet, and in some cases it may not be possible to fully avoid the allergen.

"The good news is that there are some excellent new medications that have recently become available which are much safer and more effective than the older steroid-based medication," Cable says. "Medication is usually required for the long term. However, the vast majority of dogs do respond very well to treatment, providing relief and leading to a happier dog and owner."

Cable's top tips for protecting your dog from an allergic reaction are:

• Stay up to date with flea control (for an insect bite allergy).
• Frequent household cleaning to prevent build-up of allergens such as dust mites.
• Wash your dog's bedding often to reduce any allergens.
• Make sure all chemical and soap products that your dog comes into contact with are rinsed off thoroughly.
• Wash your dog regularly with a good quality shampoo to reduce build-up of allergens and bacteria.
• Dry your dog carefully, especially in its skin folds, ears and feet.
• Put a buster collar on your dog immediately if it is licking or scratching excessively.
• Keep an "itch diary" to help track possible causes.
• Make an appointment with your vet if your dog starts itching excessively.