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Lumps And Bumps

Skin diseases are common problems in the horse. The causes of skin disease in the horse can vary from allergic reactions and infectious diseases to tumours. Some skin diseases can cause the horse significant discomfort but others may not bother the horse at all.

Grooming gives you the opportunity to examine your horse’s skin regularly and spot any changes early. Certain areas of the body are particularly prone to getting skin nodules such as the skin around the eyes, the sheath or udder and the area under the tail; it is therefore important to look at these areas closely.

Skin disease can present in a variety of different ways from loss of hair to large ulcerated nodules. If you are concerned about a lump or bump you have found on your horses skin then you should call your vet for advice or a visit. It is particularly important to contact your vet if there are lots of lumps which have appeared suddenly or over a period of time, the lump is growing or changing, the lump becomes sore or ulcerated, your horse is bothered by the lump or your horse is unwell.

The vet will want to know lots of details about your horse’s lifestyle, when the lump fist appeared, how it has changed, if any other horses on the yard are affected. It is often useful to photograph lumps and bumps to allow you to monitor them and to give your vet as much information as possible. Measuring lumps once a week will also help to determine how quickly they are growing.

Your vet will start by asking lots of questions about your horse and the lump in order to piece together a picture and find out what might have caused it.

Some lumps are very characteristic of certain diseases for example a melanoma under the tail of a grey horse. In some cases however it is more difficult to tell just by looking what the lump is, in this case your vet may decide that a biopsy is required. A biopsy is where your vet takes a sample of tissue from the lump or sometimes takes the whole lump and sends it to a pathologist to be examined.

Some lumps such as grass warts will regress on their own and do not require treatment but do require careful monitoring, others require aggressive treatment so finding out what the lump is, is very important.

There are many different types of lumps and bumps that horses get but here are some of the most common.


These are very common tumours of the skin of horses. They do not tend to spread to the internal organs but they can grow very big and cause the horse problems, especially if they are in certain areas such as around the eye or by the sheath. There are many different treatments for sarcoids depending on what type they are, how big they are and where they are.


These are tumours arising from pigment cells in the skin usually of grey horses. They are found most commonly under the tail, in the eye and under the skin around the jaw line. They can spread to the internal organs and can cause very severe problems such as colic. The treatment for melanomas is very limited.

Squamous cell carcimomas

These are tumours found in the un-pigmented (pink) skin such as in the conjunctiva of the eye and on the penis. They do not tend to spread to internal organs but can cause problems if they become big or ulcerated locally. The treatment for squamous cell carcimomas varies depending on where they are and how big they are.


This is an allergic type reaction in which the horse has multiple lumps over its body which often appear quickly. The allergen can vary but it may be insect bites, dust from hay, nettles or other plants or other allergens in the environment. Horses can sometimes be very itchy with urticaria.

There are many other causes of skin lumps and so it is always better to ask your vet for advice, even though many are benign and will not cause your horse any problems some can be very aggressive and need urgent treatment.