Is Prednisolone Safe for Horses with Laminitis, EMS or Cushing’s Disease?

By Dr Duncan Houston

Prednisolone can be extremely effective for horses with asthma, severe allergies, inflammatory skin disease and some immune-mediated conditions. The hesitation begins when that horse also has equine metabolic syndrome, pituitary pars intermedia dysfunction, previous laminitis or active foot pain.

The concern is understandable. Corticosteroids can alter glucose and insulin regulation, while persistent hyperinsulinaemia is a recognised driver of endocrinopathic laminitis. However, the research does not support the simple claim that therapeutic prednisolone routinely causes laminitis in otherwise healthy horses.

The real question is not whether prednisolone is universally safe or universally dangerous. It is which horse is receiving it, why they need it, how it is being administered and what pre-existing laminitis risks are already present.

Quick Answer

Oral prednisolone has not been shown to increase laminitis incidence across the general equine population when used therapeutically. However, horses with previous laminitis, equine metabolic syndrome, insulin dysregulation, excess body condition or PPID-associated hyperinsulinaemia require substantially more caution.

Prednisolone should not automatically be withheld when it is genuinely needed, but the individual horse’s metabolic and hoof history should be assessed first whenever circumstances allow. (Beva)

What Is Prednisolone Used for in Horses?

Prednisolone is an active glucocorticoid medication that suppresses inflammation and modifies immune activity.

Veterinarians may prescribe it for conditions including:

• Equine asthma

• Severe urticaria or allergic skin disease

• Insect bite hypersensitivity

• Inflammatory airway disease

• Certain immune-mediated skin, blood or systemic diseases

• Severe inflammatory conditions that have not responded adequately to safer local treatments

Systemic glucocorticoids can be highly effective, but they are not harmless medications. Their benefits must be balanced against possible effects on insulin regulation, immune defence, wound healing and the hypothalamic-pituitary-adrenal axis. (Wiley Online Library)

Prednisolone Is Not the Same as Prednisone

The names are often confused, but this distinction matters in horses.

Prednisone must be converted by the body into active prednisolone. Research in horses found that oral prednisone was poorly absorbed and rarely converted effectively, while oral prednisolone was absorbed rapidly and had good biological activity. Prednisolone is therefore generally preferred when an oral glucocorticoid is required. (PubMed)

Does Prednisolone Cause Laminitis in Horses?

Current evidence suggests that therapeutic oral prednisolone does not substantially increase laminitis risk across the general equine population.

That does not mean the risk is zero for every horse.

What the Major Prednisolone Study Found

A retrospective study reviewed 416 horses treated with oral prednisolone and compared them with 814 time-matched horses that had received veterinary attention but were not treated with prednisolone.

Among the prednisolone-treated horses:

• 16 of 416 horses, or 3.8%, were diagnosed with laminitis at some point after starting treatment

• Seven horses, or 1.7%, developed laminitis while they were actively receiving prednisolone

• Three horses, or 0.7%, were ultimately euthanised because of laminitis

Among the untreated controls:

• 46 of 814 horses, or 5.7%, developed laminitis during the study period

• Twelve horses, or 1.5%, were euthanised because of laminitis

The researchers found no statistically significant difference in laminitis incidence or probability between the treated and untreated groups. Increasing age and equine metabolic syndrome, rather than prednisolone treatment itself, were associated with greater laminitis risk. (Beva)

What a Larger Corticosteroid Study Found

A separate multicentre study followed 1,565 horses treated with various corticosteroids. Ten horses developed laminitis during treatment or within 14 days after the corticosteroid course ended, giving a period prevalence of 0.6%.

The most important findings were the pre-existing risk factors:

• Horses with a previous history of laminitis or an underlying endocrinopathy had approximately 18 times higher odds of developing laminitis

• Overweight or obese horses had approximately four times higher odds

• Ponies also appeared to be at increased risk in the initial analysis

The overall rate was low, but it was not distributed equally across all horses. (BVA Journals)

What Do These Studies Actually Prove?

The studies provide reasonable reassurance that corticosteroids do not commonly trigger laminitis in metabolically healthy adult horses when veterinarians select and treat cases appropriately.

They do not prove that prednisolone can never contribute to laminitis.

Both major studies were observational rather than randomised trials. Veterinarians may already have avoided corticosteroids in horses considered particularly vulnerable, which could make the treated population safer than an unselected population. Mild laminitis may also have been missed if an owner did not recognise it or arrange another examination.

The most defensible clinical interpretation is this:

Prednisolone does not appear to be a major independent laminitis trigger in the average horse, but it may amplify or expose an existing vulnerability in a horse with insulin dysregulation, endocrine disease, previous laminitis or obesity.

That interpretation is consistent with both the clinical incidence studies and the experimental evidence showing that some corticosteroids affect insulin and glucose regulation. (Beva)

Why Are Veterinarians Still Cautious About Corticosteroids?

The concern is biologically plausible because glucocorticoids can interfere with insulin sensitivity and glucose metabolism.

In one experimental study, healthy horses receiving dexamethasone over 21 days developed markedly reduced insulin sensitivity and increased insulin responses. This did not directly prove that laminitis would occur, but it demonstrated a metabolic change associated with greater laminitis susceptibility. (PubMed)

More recent studies involving intra-articular triamcinolone found temporary increases in blood glucose and insulin, even in horses initially classified as having normal insulin regulation. Horses with higher baseline insulin concentrations developed a much larger insulin response following corticosteroid administration. (PubMed)

These studies involved different corticosteroids, doses and routes of administration. They should not be treated as direct proof that oral prednisolone has identical effects. They do show why a horse’s baseline insulin regulation matters.

Why Does Insulin Matter So Much?

Persistent hyperinsulinaemia can directly damage the hoof lamellae.

In an experimental model, otherwise healthy horses subjected to prolonged hyperinsulinaemia developed laminitis within approximately 48 hours. Early signs included stronger digital pulses, restlessness and shifting weight, followed by a stiff gait and difficulty turning. (Beva)

This is why the main concern in a horse with EMS or PPID is not simply the diagnostic label. The critical question is whether that horse also has insulin dysregulation or hyperinsulinaemia.

How Do EMS and PPID Change the Risk?

Equine Metabolic Syndrome

Insulin dysregulation is the central abnormality in equine metabolic syndrome. Affected horses may produce an excessive insulin response after consuming sugar or starch, remain hyperinsulinaemic for prolonged periods or have reduced tissue insulin sensitivity.

Common clues include:

• A cresty neck

• Regional fat deposits

• Generalised obesity

• Recurrent or unexplained laminitis

• Abnormal hoof growth rings

• A history of becoming footsore on pasture

• A pony or thrifty breed phenotype

Not every horse with EMS is visibly overweight. Lean horses can still have clinically important insulin dysregulation. (Beva)

Pituitary Pars Intermedia Dysfunction

PPID, commonly called equine Cushing’s disease, is an age-related endocrine disorder. However, PPID and insulin dysregulation are not the same condition.

A horse may have PPID without hyperinsulinaemia. Another horse may have both PPID and insulin dysregulation, and it is the combination that creates the greater laminitis concern.

Evidence-based PPID guidelines state that horses with PPID and hyperinsulinaemia appear to face greater laminitis risk, while ACTH concentration itself is not an independent predictor of laminitis. Horses with laminitis, regional adiposity or bulging fat above the eyes should therefore be assessed for insulin dysregulation rather than having only an ACTH test performed. (Beva)

Research examining hoof tissue from PPID horses also found that lamellar disease was associated with hyperinsulinaemia. PPID horses without laminitis had insulin concentrations within the reference range and normal lamellar tissue in that study. (PubMed)

Previous Laminitis

A previous laminitis episode is one of the strongest practical warning signs.

Even when the horse appears sound today, previous laminitis suggests that the feet have already demonstrated vulnerability. Hyperinsulinaemia and previous laminitis are both associated with greater recurrence risk. (PubMed)

Practical Prednisolone Risk Framework

This is a clinical decision framework rather than a formally validated scoring system.

Lower Risk

The horse:

• Has no history of laminitis

• Has normal body condition

• Has no regional fat deposits or cresty neck

• Has no signs of PPID

• Is receiving a short, medically justified course

• Has no major pasture or dietary risk occurring at the same time

Action: Prednisolone may be reasonable when prescribed appropriately. Routine observation of movement, digital pulses and appetite remains sensible.

Moderate Risk

The horse:

• Is older

• Is a pony or thrifty breed

• Is overweight

• Has a cresty neck or regional fat deposits

• Has an unknown insulin status

• Requires repeated or prolonged steroid treatment

• Has mild hoof changes without confirmed previous laminitis

Action: Discuss insulin testing and possible PPID testing before treatment when the condition is not immediately life-threatening.

High Risk

The horse has:

• Confirmed insulin dysregulation or EMS

• Previous laminitis

• PPID with hyperinsulinaemia

• Significant obesity

• Recent unexplained foot soreness

• Active exposure to lush pasture or a high-sugar diet

• Multiple overlapping risk factors

Action: Prednisolone should only be used after a deliberate risk-benefit assessment. Consider alternatives, establish a hoof-monitoring plan and control dietary and pasture risks before treatment where possible. The substantially higher risk associated with previous laminitis, endocrinopathy and excess body condition is supported by clinical cohort data. (BVA Journals)

Critical Situation

The horse currently has:

• Active laminitis

• A strong or bounding digital pulse

• Marked pain turning

• A short, stilted gait

• Reluctance to walk

• Repeated weight shifting

• Pain affecting several feet

Action: Contact the veterinarian immediately. Any decision about starting, continuing, reducing or replacing prednisolone must be made alongside urgent laminitis management.

Should Horses Be Tested Before Starting Prednisolone?

Not every healthy horse receiving a brief, urgent course requires an exhaustive endocrine investigation.

Testing becomes much more important when the horse has recognised risk factors.

Consider pre-treatment testing when there is:

• Previous laminitis

• A cresty neck or regional adiposity

• Obesity

• Unexplained foot soreness

• Divergent hoof rings

• A pony or thrifty breed phenotype

• Age-related PPID signs

• Delayed coat shedding or hypertrichosis

• Increased drinking or urination

• Muscle loss

• Recurrent infections

• A need for prolonged or repeated steroid treatment

Which Tests May Be Useful?

Testing may include:

• A resting or fed insulin concentration

• An oral sugar test

• Blood glucose interpreted alongside insulin

• Basal ACTH testing when PPID is suspected

• A TRH stimulation test in selected PPID cases

A normal resting insulin concentration does not completely exclude insulin dysregulation. In one field study, basal insulin had lower sensitivity than an oral sugar test or insulin tolerance test. Dynamic testing may therefore be more informative when clinical suspicion remains high. (PubMed)

Testing must also be interpreted according to the assay, feeding conditions, season and the horse’s clinical signs. There is no single insulin number that should be copied between every laboratory and every testing protocol.

Do Not Delay Essential Treatment Without Good Reason

If a horse is in serious respiratory distress or has a potentially life-threatening immune-mediated disease, waiting days for a perfect endocrine work-up may create more danger than carefully administered prednisolone.

When feasible, baseline blood samples can be collected before the first dose without unnecessarily delaying treatment.

Can Prednisolone Be Used During Active Laminitis?

Active laminitis substantially changes the decision.

Systemic prednisolone would not normally be chosen as a treatment for endocrinopathic laminitis itself. If it is being considered for an unrelated condition, the veterinarian must weigh:

• How serious the other disease is

• Whether a non-steroidal alternative exists

• Whether local or inhaled treatment could work

• The horse’s current insulin status

• The severity and stability of the laminitis

• The expected steroid dose and duration

• Whether the horse can be monitored closely

There are situations where controlling severe asthma, anaphylaxis or immune-mediated disease may still be essential despite laminitis risk. A blanket refusal to use any corticosteroid can be just as unsafe as using one casually.

Do not independently stop a prescribed course because the horse has become footsore. Contact the prescribing veterinarian immediately. The primary disease, steroid dose, treatment duration and need for tapering must all be considered.

How Can Prednisolone Be Used More Safely?

1. Confirm That a Systemic Steroid Is Actually Needed

Prednisolone should have a clear therapeutic purpose. It should not become the default answer for every cough, itch or unexplained skin lesion.

Diagnosis matters because infection, parasites, environmental irritation and neoplasia may worsen or remain untreated if inflammation is suppressed without addressing the cause.

2. Use the Lowest Effective Exposure

The goal is generally to:

• Use the lowest dose that controls the disease

• Use the shortest effective course

• Reduce the dose according to the veterinarian’s tapering plan

• Avoid unnecessary repeated courses

• Reassess rather than automatically renewing medication

For chronic allergic skin disease, consensus guidance recommends reducing systemic glucocorticoids to the lowest dose and frequency that maintains control, rather than relying indefinitely on high-dose therapy alone. (Wiley Online Library)

3. Control Other Laminitis Risks

Do not combine a steroid course with avoidable metabolic challenges.

For a horse with known insulin dysregulation:

• Maintain the prescribed low non-structural carbohydrate feeding plan

• Avoid grain, molasses and sugary treats

• Control or remove pasture access according to veterinary advice

• Avoid sudden dietary changes

• Monitor body condition and cresty neck size

• Continue appropriate PPID treatment

• Maintain regular farriery care

A lean PPID horse should not automatically be subjected to severe calorie restriction. Diet must account for body condition, muscle mass, dental health and insulin status. (Beva)

4. Establish the Horse’s Normal Digital Pulses

Learn what the horse’s digital pulses feel like before treatment. This makes a meaningful change easier to identify.

Check both front feet and, where relevant, all four feet. Compare sides and assess the whole clinical picture rather than relying on hoof temperature alone.

5. Monitor Movement Every Day

Watch the horse:

• Walking in a straight line

• Turning in both directions

• Stepping out of the stable

• Moving over firm ground without being forced

• Standing quietly at rest

Difficulty turning, reluctance to walk, shifting weight, a short stilted gait and increased digital pulses are among the most useful clinical indicators of laminitis. (PubMed)

6. Continue Monitoring After the Final Dose

The larger corticosteroid cohort specifically monitored horses through 14 days after treatment ended. A practical approach is to remain particularly alert during treatment and for approximately two weeks afterwards, although the exact risk period will vary with the drug, route, dose and individual horse. (BVA Journals)

7. Reassess Prolonged or Repeated Treatment

If the horse requires continuing systemic prednisolone, review:

• Whether the original diagnosis remains correct

• Whether the dose can be reduced

• Whether inhaled or topical treatment could replace part of the systemic therapy

• Whether insulin testing should be repeated

• Whether PPID remains adequately controlled

• Whether the feet show subtle changes

• Whether infection or other steroid-related complications have developed

When Is This an Emergency?

Treat new foot pain during or shortly after corticosteroid treatment as urgent when the horse develops:

• Reluctance to walk

• A short, stiff or stilted gait

• Difficulty turning

• Repeated shifting of weight

• Stronger digital pulses in multiple feet

• Bilateral forelimb lameness

• A rocked-back stance

• Unusual time spent lying down

• Sudden refusal to leave the stable

• Rapidly worsening foot pain

Bilateral forelimb lameness combined with increased digital pulses is particularly suggestive of laminitis rather than a single localised limb injury. (PubMed)

What To Do Right Now

1. Call your veterinarian.

2. Do not force the horse to walk or circle repeatedly. Turning can be particularly painful in early laminitis.

3. Keep the horse in a small, safely confined area with supportive deep bedding while awaiting veterinary instructions.

4. Remove grain, sugary feeds and access to lush pasture. Continue water and follow veterinary advice about appropriate forage.

5. Do not independently give additional medication or change the prednisolone dose.

6. Tell the veterinarian exactly when the steroid was started, the current dose, the last dose given and whether the horse has EMS, PPID or previous laminitis.

Are There Safer Alternatives to Systemic Prednisolone?

The answer depends entirely on the disease being treated.

Equine Asthma

Environmental control is essential. Medication cannot permanently compensate for continued heavy exposure to respirable dust and airway irritants.

Options may include:

• Maximising turnout where appropriate

• Replacing dry, dusty forage with a lower-dust alternative

• Improving stable ventilation

• Changing dusty bedding

• Using properly prepared soaked or processed forage where suitable

• Inhaled corticosteroids

• Bronchodilators as part of an appropriate treatment plan

Inhaled corticosteroids are effective for equine asthma and may reduce the need for systemic treatment. A meta-analysis of four clinical trials involving 252 horses found that inhaled corticosteroids significantly increased the likelihood of clinical improvement. A large clinical trial also found inhaled ciclesonide effective and generally well tolerated in horses with severe asthma. (PubMed)

An inhaled corticosteroid is still a corticosteroid. Systemic absorption may be lower, but it should not automatically be considered risk-free in every metabolically vulnerable horse.

Insect Bite Hypersensitivity and Allergic Skin Disease

Depending on the diagnosis, management may include:

• Effective insect avoidance

• Fly rugs and masks

• Appropriate repellents

• Moving the horse indoors during peak insect activity

• Treating secondary bacterial or fungal infection

• Localised topical therapy

• Allergen-specific immunotherapy in appropriate cases

• Selected antihistamines as adjunctive treatment

For insect bite hypersensitivity, current consensus guidance identifies insect avoidance as the most effective long-term strategy. Antihistamines are not reliably effective as sole treatment, and long-term systemic glucocorticoids should not be the only management strategy. (Wiley Online Library)

Localised Inflammatory Disease

Topical, inhaled, ophthalmic, intrasynovial or other local treatments may sometimes reduce total systemic exposure.

However, “local” does not always mean “no systemic absorption.” Corticosteroids administered into joints and even some topical formulations can reach the circulation. The product, location, dose and frequency still matter. (PubMed)

Immune-Mediated Disease

There may be no simple substitute for systemic immunosuppression.

Alternative immunomodulatory medications may be slower, more expensive or carry their own serious risks. In these cases, prednisolone may remain the most appropriate treatment despite metabolic concerns.

Common Mistakes Owners Make

Assuming Steroids Always Cause Laminitis

The evidence does not support this. Most appropriately selected horses receiving therapeutic corticosteroids do not develop laminitis.

Assuming Steroids Never Cause Laminitis

The absence of a population-wide increase does not guarantee safety in a horse with EMS, previous laminitis or hyperinsulinaemia.

Treating PPID and Insulin Dysregulation as the Same Thing

A PPID diagnosis alone does not reveal the horse’s insulin status. Both may need to be tested and managed separately.

Checking Glucose but Not Insulin

Many insulin-dysregulated horses do not have obvious persistent hyperglycaemia. A normal glucose result does not rule out an excessive insulin response.

Stopping Prednisolone Suddenly Without Advice

Changing the treatment may allow the original disease to rebound and may be inappropriate after sustained treatment. Contact the prescribing veterinarian for a safe plan.

Relying on Medication While Ignoring the Trigger

A dusty stable, dry hay or ongoing insect exposure will continue driving disease after the steroid is reduced.

Waiting for the Classic Rocked-Back Stance

Not every early laminitis case looks dramatic. Difficulty turning, a shortened gait and increased digital pulses may appear first.

Frequently Asked Questions

Can one dose of prednisolone cause laminitis?

Laminitis after a single therapeutic dose appears uncommon, particularly in a metabolically healthy horse. However, no dose can be declared universally risk-free for every horse, especially one with severe insulin dysregulation or previous laminitis.

Can a horse with PPID take prednisolone?

Sometimes, yes. PPID is not an automatic absolute contraindication. The more important questions are whether the horse also has insulin dysregulation, whether laminitis has occurred before and whether a safer treatment can control the current disease. (Beva)

Should insulin be tested before giving steroids?

Testing is particularly worthwhile in horses with previous laminitis, obesity, a cresty neck, a pony phenotype, PPID or a need for prolonged treatment. An urgent, potentially life-saving steroid course should not necessarily be delayed, but baseline samples can often be collected first.

Is prednisolone safer than dexamethasone?

There is not enough direct comparative evidence to promise that one is universally safer from a laminitis perspective. Potency, dose, duration, route and the horse’s metabolic status all matter. Evidence that dexamethasone and triamcinolone alter insulin regulation supports caution, but those findings should not be directly substituted for prednisolone-specific risk data. (PubMed)

Is inhaled steroid treatment safe for a horse with EMS?

Inhaled treatment may reduce systemic exposure and can be effective for equine asthma, but it is not automatically risk-free. The veterinarian should still consider the horse’s previous laminitis and insulin status, particularly when treatment is prolonged. (PubMed)

Final Thoughts

Prednisolone is not automatically forbidden in horses with EMS, PPID or a history of laminitis. It is also not a medication that should be prescribed casually in these horses.

The best available clinical evidence suggests that therapeutic prednisolone does not meaningfully increase laminitis incidence across the general equine population. The risk changes sharply when the horse already has insulin dysregulation, previous laminitis, an endocrinopathy or excess body condition.

The safest approach is to assess the individual horse, confirm that systemic treatment is necessary, reduce avoidable metabolic risks and monitor the feet closely during and after treatment.

Most metabolically healthy horses treated appropriately will not develop laminitis. For a vulnerable horse, early recognition of stronger digital pulses, difficulty turning or a shortened gait can make the difference between prompt intervention and a much more serious hoof emergency.

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