Household Horrors – The indoor allergens lurking in your home

When environmental allergy is mentioned, often pollen is the first thing that springs to mind (no pun intended). You visualise someone suffering with the classic hay fever symptoms; itchy eyes, sneezing and a runny nose, after exposure to whichever tree or plant is their trigger. However, indoor allergens are remarkably common in dogs, cats, horses and humans and can cause serious skin and respiratory problems for all species.

Below we discuss the top 5 indoor allergens and provide practical tips on how to reduce exposure to them.


These mites are very small and almost transparent. They eat dead skin flakes from both humans and pets. It is the dust mite faeces and dead body parts when either inhaled or touched, rather than the live dust mites themselves, that provoke an allergic reaction. The mites live in bedding, upholstered furniture, carpets, curtains, mattresses and pillows. An estimated 100,000 – 10 million mites live in a typical used mattress and 10% of the weight of a two-year old pillow is supposedly made up of dead mites and their droppings1.

Removing dust mites completely from the environment is impossible, but there are procedures to reduce their presence such as:

  • Vacuuming or dry-cleaning your carpets, curtains and upholstery regularly
  • Turning down the central heating (they thrive in warm temperatures)
  • Washing your pet’s bedding and stuffed toys regularly at hot temperatures or freezing them, e.g. freeze the soft toy for 24hrs to kill the mites then wash to remove the body parts
  • Not allowing your pet to sleep in your bedroom as this is the dust mite hotspot in the home


Storage mites are tiny, white arachnids that feed on stored foods such as flour, grain and seeds. Management of your pet’s food can greatly reduce their exposure to storage mites. This involves avoiding foods where storage mites are known to be prevalent; in particular in poorly stored dry complete diets.

If dry foods are fed, we would recommend:

  • Always emptying the food from the original packaging into resealable plastic containers and discarding the dust at the bottom of the bag
  • Cleaning the plastic containers regularly, again discarding any dust at the bottom and always doing this before adding any new food
  • Keeping the food in dry, cool conditions
  • Purchasing only small bags of food rather than large bulk packs to ensure fresher batches are fed
  • Wiping your pet’s face with a damp cloth when it has finished feeding to remove any food residue
  • Feeding wet/tinned foods or a home prepared diet instead of dry food
  • Never using any foods after the use-by date


Moulds are a type of fungus and  like warm, damp and humid conditions best. They spread by producing tiny spores which are too small to see but float through the air. When these spores are inhaled or touched, they can cause an allergic reaction. This results in similar symptoms to hay fever; itchy eyes, sneezing, runny nose and also a skin rash. To reduce the amount of mould in your home it’s important to make the environment difficult for mould to live in by reducing the dampness.


Fleas are a major insect pest to our pets. Not only do they cause discomfort by biting, but they can also transmit disease. Some animals have a heighted response to flea bites (known as flea allergic dermatitis), which means they have an allergic response to the bite rather than it just causing the normal irritation and inflammation. In these animals, even a few flea bites can trigger extremely itchy and irritated skin.

The aim of flea control is to eliminate the adult flea and all other stages of the life cycle. Female fleas can lay up to 50 eggs every day meaning that for every live flea seen on your pet, there will lots more eggs waiting to hatch in your home. All control measures used for house dust mites apply to fleas. There are also a number of flea preparations that can be given to/used on your pet and in the environment. Your veterinary surgeon will advise on the most appropriate method for you.


It’s not only people that have allergies to cats, some dogs do too! The allergy is caused by a protein present in the tiny flakes of dead skin (dander) and the cat’s saliva. The saliva sticks to the fur when the cat grooms itself.

We recommend the following measures to help reduce your dog’s exposure to cat dander:

  • Grooming your cat at least once a week either outside or in a well-ventilated room away from the dog
  • Washing the pet’s bedding once a week
  • Washing your hands in between handling the cat and the dog

If you think your pet may have an indoor allergy, contact your veterinary practice to discuss the best way of investigating it further. An allergy blood test to identify indoor allergens may be suggested as part of this process.

Written by Johanna Forsyth– Senior Veterinary Technical Manager


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