Understanding Steroids in Equine Care: When They’re Used - and What to Consider

Owners sometimes contact us after their horse has been prescribed a course of steroid medication, usually for a skin condition. They may have heard about possible side effects and want to understand more. Occasionally, they ask whether there are “non-steroid alternatives”.

Steroidal medicines can only be prescribed by a veterinary surgeon. They are powerful drugs designed to influence the body’s inflammatory and immune responses. Used appropriately, they can be extremely effective - and in some cases, life-saving.

How steroids work

The most commonly used steroids in equine veterinary care are glucocorticoids, synthetic versions of cortisol, a hormone naturally produced by the adrenal glands. Their primary function is to suppress inflammation and dampen overactive immune responses.

In acute situations - such as severe allergic reactions, hives, airway inflammation, or sudden inflammatory flare-ups - they can bring rapid relief and stabilise the horse quickly.

For short-term use under veterinary guidance, they are widely considered safe and effective.

My own horses have been successfully treated with steroid medicines in the past for mud fever, injured tendons and a severe case of hives. In each case, they cleared up in a short time and did not appear to cause any ill-effects.

But in contrast, I recently heard from an owner who thought the 4 week steroid course had completely changed her horse’s demeanour. He changed from an easy-going type, friendly with his yard companions to being nervy and reactive with other horses. It did help his skin condition but the owner understandably discontinued its use. In this case, the steroidal medicine affected more than the target organ - the skin – as it seemed to cross-react with natural hormones that affected behaviour.

An example of longer-term steroid use on horses is the Insol injection, a glucocorticoid originally designed for ringworm, which some vets have started to offer in order to help alleviate sweet itch symptoms. It is early days as far as scientific trials are concerned, and anecdotal evidence seems very mixed at this juncture – with some horse owners reporting a perceived improvement in itching and rubbing behaviour, and others far less convinced it was worth the (not insignificant) costs and risk. With so many variables involved in a ‘sweet itch season’, not least geographical location and weather, it is perhaps not surprising that results are inconclusive.

Where caution is needed

Steroids influence far more than the visible symptom. Because they act on hormonal pathways, their effects can extend beyond the target tissue.

With longer-term or repeated use, potential risks may include:

• Reduced insulin sensitivity
• Increased laminitis risk in predisposed horses
• Behavioural changes
• Suppression of natural immune responses

This does not mean they should be avoided — but it does mean they warrant careful veterinary oversight, particularly in horses with additional risk factors such as age, weight, or metabolic conditions.

Personally, I would definitely think twice about using steroids long-term and most definitely not as a performance enhancer. Some vets might be persuaded to prescribe steroid medicines for opening up airways, encouraging muscle growth (anabolic), and changing behaviours if the owner so desires and can afford to pay, but it’s a fine line to tread to stay on the side of legality and morality. In some industries, the prizes and outcomes are deemed more desirable than the long-term health of the animal. There are legal hurdles in place to discourage inappropriate use of steroids in competition, but vets can be persuaded to prescribe a drug for a stated purpose which may inadvertently increase competitiveness.

Steroid use in horses can have a variety of risks, including reproductive issues, liver damage, behavioural issues, weight gain, and muscle damage. Side effects and contra-indications may not present immediately until some damage has been done. Specific steroids fall in and out of favour with vets when the full extent of their action emerges.

For example, Methylprednisolone acetate (Depo-Medrol) is an important steroid widely used in joint injuries and arthritis, but it is under scrutiny for association with accelerated joint deterioration over time. This may be because the effect of the steroid is to mask the pain and inflammation allowing the joint to be overused and further damaged.

If you choose to go down a steroid route, open discussion with your vet about expected duration, dosage, and monitoring is always advisable.

And it’s always a good idea to check ingredients very carefully or question whether a medication may contain steroids. Over-the-counter human use medicines, such as hydrocortisone creams are steroids and shouldn’t be used on animals. Any drug with the affix sterol, sone or sol is likely to be a steroid, so check carefully what you are ordering or being prescribed.

Skin conditions and recurrence

In the context of mud-related skin conditions, steroids may reduce inflammation and improve comfort quickly. However, they do not address underlying contributors such as prolonged moisture exposure, bacterial load, or a compromised skin barrier.

If these factors remain unmanaged, recurrence can be common once medication is withdrawn.

This is where practical, environmental and topical management become important - not as a replacement for veterinary care, but as part of a more complete approach.

Informed decisions matter

Steroids can be invaluable tools in equine medicine. They have extended and improved the lives of many horses. However, like all powerful medicines, they are not risk-free.

Understanding:

• Why they are being prescribed
• What they are expected to achieve
• How long should they be used
• What the potential longer-term implications are

helps owners make calm, informed decisions in partnership with their vet.

Where skin health is concerned, supporting the integrity of the skin barrier and reducing environmental stressors may reduce reliance on repeated intervention over time.

Practical guidance. Informed choices. Long-term thinking.

 

Frequently Asked Questions About Steroids in Horses

What are steroids used for in horses?

Steroids are commonly prescribed to reduce inflammation and suppress overactive immune responses. They may be used for allergic reactions, skin conditions, joint inflammation, airway issues, and certain autoimmune conditions.

How do steroids work in horses?

Most veterinary steroids are glucocorticoids, synthetic versions of cortisol. They reduce inflammation by dampening the immune system’s response, which can quickly relieve swelling, itching, pain, or airway restriction.

Are steroids safe for horses?

When used short-term under veterinary supervision, steroids are widely considered safe and effective. Risks are more likely to arise with repeated or long-term use, particularly in horses with metabolic or underlying health conditions.

What are the possible side effects of steroids in horses?

Potential side effects may include:

• Increased laminitis risk in predisposed horses
• Reduced insulin sensitivity
• Behavioural changes
• Suppression of immune function
• Weight gain or muscle changes
• Liver strain with prolonged use

Not every horse will experience side effects, but monitoring is important.

Can steroids change a horse’s behaviour?

In some cases, yes. Because steroids influence hormonal pathways, behavioural changes such as increased reactivity or nervousness have been reported. If behaviour shifts noticeably during treatment, this should be discussed with your vet.

Can steroids cause laminitis?

Steroids may increase laminitis risk, especially in horses that are overweight, older, or have metabolic conditions such as insulin dysregulation. Risk depends on dose, duration, and individual susceptibility.

Are steroids ever used long term in horses?

They can be, but long-term use requires careful veterinary oversight. The lowest effective dose for the shortest appropriate duration is typically preferred to reduce risk.

Should steroids be used as performance enhancers?

Steroids should only be used for legitimate medical reasons prescribed by a veterinary surgeon. Using them to enhance performance raises welfare, ethical, and regulatory concerns.

Do steroids cure skin conditions?

Steroids reduce inflammation and improve comfort, but they do not always address the underlying cause of a skin issue. If environmental factors, moisture exposure, or bacterial load remain unmanaged, recurrence may occur once medication stops.

Are steroids effective for sweet itch in horses?

Steroids may reduce the inflammation and itching associated with sweet itch during flare-ups. However, they do not address the allergic trigger, and symptoms may return when treatment ends.

What is the Insol injection used for?

The Insol injection is a glucocorticoid originally developed for ringworm. Some vets now use it to help manage sweet itch symptoms, although scientific evidence is still emerging and owner experiences appear mixed.