Indoor allergen avoidance and/or reduction

Avoiding offending allergens should always be considered, however due to the airborne nature of some indoor environmental allergens, avoidance may not always be possible (for example mould spores). In these cases, your vet may also recommend treatment or therapy to control the symptoms.

Click the different sections below for valuable tips on avoiding/reducing moulds, dust mites, storage mites and other indoor allergens that might be present in your horse’s environment.

House dust mites are a common cause of allergy in the UK. These mites are very small and almost transparent. It is dust mite faeces rather than the dust mites themselves that provoke the allergic reaction.

A teaspoon of dust may contain more than 250,000 mite droppings! They prefer warm, humid conditions and it is suspected that they live in general stable dust, hay, bedding and fabrics. They have also been found in horse’s rugs.

They require moisture from the air to digest their food, so humidity influences the size of the mite populations. Removing dust mites from the environment is impossible, but there are procedures to reduce their presence.

House Dust Mites – Hints and Tips

  • Try to wash or change your horse’s rug, and other textiles such as saddle cloths, as much as possible to keep fabrics mite free
  • Wash rugs and other textiles at hot temperatures and dry in the sun when possible as mites struggle in hot dry conditions
  • Store rugs over winter (once thoroughly clean and dry) in air tight packaging
  • Try to get rugs and other textiles dry as soon as possible to avoid damp conditions
  • Reduce humidity and increase ventilation in your horse’s stable
  • Regularly dust your horse’s stable to decrease the food sources available to the mites
  • Try to source good quality dust free hay for your horse
  • Buy smaller bales of forage to prevent build-up of dust


Storage Mites

Dry cereal-based feeds are commonly fed to horses which is where storage mites are commonly found.

Two of the most common types of storage mite found in the UK are included on the SENSITEST® indoor allergy panel – Acarus siro and Glycophagus destructor.

Storage mites are tiny, white insects that feed on stored foods such as flour, grain and seeds. Management of your horse’s food can greatly reduce their exposure to storage mites.


Storage Mites – Hints and Tips

  • Always empty the food from the original packaging into resealable plastic containers discarding the dust at the bottom of the bag.
  • Clean these plastic containers regularly, again discarding any dust at the bottom and always do this before adding new food.
  • Rinse your horse’s feed bucket daily
  • Keep the food in dry, cool conditions.
  • Purchase only small bags of food rather than large bulk packs to ensure fresher batches are fed.
  • Wipe your horse’s muzzle with a damp cloth when it has finished feeding to remove any food residues.
  • Never use any foods after the use by date.



A mould or fungus is a microscopic, plant like organism that grows on organic material. You will have no doubt seen examples of mould when your bread has gone past its sell by date or when fruit has gone stale.

Moulds are found throughout the natural world and are essential for the recycling of organic material in our forests, lawns and gardens. They all require a relatively damp environment to grow. Many moulds reproduce by releasing spores into the air, which then settle on organic matter and grow into new mould clusters. These airborne mould spores are far more numerous than pollen.

Moulds – Hints and tips

  • Keep stables well ventilated and treat damp walls with a mould inhibitor
  • Don’t allow mould to form in damp areas of stabling
  • Check any food sources – ensure they are kept in dry conditions and there is no sign of mould or rot especially on fruit and vegetables.
  • Treat any damp walls with a mould inhibitor.
  • Avoid heavy vegetation and climbing plants such as ivy, around or over barns and stabling
  • Keep the stable yard free of fallen leaves and other plant debris
  • Try to position the muck heap away from / up wind from stabling
  • Keep tack dry and clean as some moulds are common on leather
  • Source good quality forage free from mould and dust
  • Keep all rugs and other textiles in dry conditions

Places where moulds are commonly found:

  • Textiles such as leather (saddles, bridles, boots etc.), rugs and saddle cloths (particularly if damp)
  • Amongst dust in your horses stable
  • Behind paint
  • Water damaged buildings
  • Moist chipboard
  • Soil and decaying plant debris (making areas such as the muck heap high risk)
  • Within damp straw, hay or haylage
  • Stored grains / cereals (feed) – care should be taken storing feed correctly to avoid this
  • Carrots – care should be taken if feeding carrots to ensure they are mould free

Specific information about different moulds:


Penicillum is also an airborne allergen spread by the wind and insects and is a food source for Storage Mites.

Alternaria tenuis

This is one of the most common airborne allergens and is spread via the wind.

Aspergillus mix

Aspergillus is also airborne and spread by the wind.

This mould is especially prevalent in the autumn & winter months and mainly flourish in damp, dark and warm places.