Equine Allergy

Equine Allergy




The peak age of onset is from 2 to 5 years for gastrointestinal and dermatological symptoms, where as respiratory symptoms tend to occur at a later stage usually 5 years or older.

Although clinical symptoms may occur in horses at any age where there is a heavy allergen load i.e pastures with a high incidence of midges, stables with high dust levels and of course the seasonal rate of pollens can vary.


It is suggested that 10-20% of horses and ponies will suffer from allergic disease at some point in their life but no accurate data is available. There is no breed or gender predilection for allergic disease in horses, however there does appear to be some inherited susceptibility for example sweet itch in Icelandic ponies.


An allergy is an immune mediated response to an external stimulant such as foods, pollens from trees, grasses or weeds, moulds, dust, storage mites and insects. Allergens can enter the body by inhalation, ingestion or absorption. Allergy can affect all types and breeds of horses/ponies. The following can be characterised as clinical signs of equine allergy:



More commonly known as hives, can occur following exposure to a whole range of possible allergens, including medicines, feed components, pollens and moulds.


The most common cause of itching is usually due to ectoparasites, allergy and infections. This may be accompanied by hair loss, scaling and subcutaneous oedema.

Summer seasonal recurrent dermatitis

Commonly known as ‘sweet itch’, this is hypersensitivity to the culicoides species and does tend to be seasonal (spring/summer). Clinical signs appear as frequent rubbing mainly around the mane and tail.


Airborne pollution from mould/fungal spores, dust mites and pollens both outdoors and in the stable can cause equine respiratory disease.

Recurrent Airway Obstruction/Chronic Obstructive Pulmonary Disease

Inflammation and narrowing of the airways along with increased mucus production. This can also be referred to as heaves or equine asthma, the condition is extremely debilitating and if left undiagnosed it can cause irreversible damage to the lungs.


Certain feeds may cause an adverse reaction resulting in diarrhoea, weight loss and pruritus.


Headshaking is an abnormal behaviour observed in some horses and often attributed to allergies

Can include unexplained and sudden changes in temperament, loss of performance in competition horses and lethargy.

For more information on the clinical signs associated with equine allergy, please download our ‘Allergies and Your Horse’ leaflet.


Here at Avacta Animal Health it is essential we always test samples at the optimum time i.e when the animal is symptomatic and ideally prior to any intervention. Therefore, if a client is reluctant to go ahead with allergy testing at first, or you would like to try certain treatment/s initially then please make use of our storage facility. Send samples to us with the submission form clearly marked “for storage” and we will store them free of charge for up to 3 months. Then if you would like to proceed with testing at any point simply call us to upgrade your sample.


Serological tests can aid diagnosis and treatment selection in cases of atopic dermatitis by providing rapid and easy identification of potential offending allergens.

Although intradermal testing (IDT) was considered the “gold standard” for the diagnosis of allergic disease, recent data has suggested that the sensitivity and specificity of IDT vs serology is comparable1.

Furthermore, there are limitations to IDT such as; extensive patient preparation, sedation often being required and interpretation requiring both experience and expertise.

The ELISA technology has the following advantages: 

  • Quick and easy – serum sample sent to laboratory
  • Requires minimal patient preparation
  • No adverse reactions
  • No need for referral
  • Standardised procedure
  • Excellent reproducibility
  • Not influenced by existing skin pathologies or medications (see our allergy withdrawal guide)

1. Favrot, C., Steffan, J., Seewald, W. & Picco, F. (2010). A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis. Vet Dermatology, 21(1):23-31.


Since 1999 we’ve been assisting companion animal veterinary surgeons with their diagnosis of allergies in dogs, cats and horses.

  • Our team of leading research and development scientists are highly regarded within the dermatology field, having submitted clinical papers and presented at successive World Congresses of Veterinary Dermatology since 2008. We work alongside leading figures and companies in veterinary dermatology.
  • SENSITEST® complete allergy tests use a monoclonal antibody to detect allergen-specific IgE antibodies, making SENSITEST® allergy tests very specific and reliable.
  • Tests are manufactured in our Yorkshire laboratory allowing for end to end control throughout the process with a specific focus on UK native species of plant allergens
  • Our knowledgeable, friendly Customer Service team are on hand to provide first-class tailored support and guidance throughout your allergy cases. Technical support is provided by a certified dermatologist.
  • Dedicated client support literature and website to inform your clients and aid compliance.
  • Personalised results packs sent out with every test.
  • Storage facility to hold samples free of charge for 3 months when you suspect allergy in your case workup, but are not ready for serological analysis.
  • Free pre-paid postal packs to send in your sample submissions.
  • Results provided within 7-10 days from receipt of sample.



  • Comprehensive food panel
  • Comprehensive indoor, outdoor and insect panel


  • Comprehensive indoor, outdoor and insect panel

Test Submission Forms

To submit a test click below or contact customer services to request a submission box.