Presenting Signs – Equine

Equine Allergy Overview

An allergy is an immune mediated response to an external stimulant such as foods, pollens from trees, grasses, 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.

Dermatological Signs


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 parasites, insects, 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). Symptoms appear as frequent rubbing mainly around the mane and tail.

Gastrointestinal Signs

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

Respiratory Signs

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.


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 symptoms of equine allergy, please download our ‘Allergy and Your Horse’ leaflet

Accurate diagnosis requires a complete detailed history, full clinical examination, evaluation of differential diagnoses and allergy testing

Click here to view the SENSITEST equine panels we run to assist in the diagnosis of equine allergy