Call your veterinarian now. That is the answer to this question and it is not a hedge: an abscess and laminitis can both produce sudden severe lameness with an increased digital pulse, and the only safe assumption is the worse one until a professional has seen the horse. There is one pattern that points, rather than proves: the Merck Veterinary Manual describes a hoof abscess as "the most common reason for a non-weight-bearing lameness in horses," usually with "acute onset of severe lameness in one limb," while in laminitis "usually, both forefeet are affected" and the horse adopts a stance with "the forelimbs placed in front of their normal position and the hindlimbs placed under the horse." One limb versus two front limbs is a pointer. It is not a diagnosis and you are not qualified to make one, and neither are we.
This page exists so that you can give your vet useful information on the phone, and so you understand why nobody honest will tell you which one it is from a description.
What each one is
A hoof abscess. Merck: "a hoof abscess is a focal accumulation of purulent exudate that most often occurs between the germinal and keratinized epithelium of the hoof," and the pain "is due to the rapid increase in pressure within the low-compliance environment of the hoof capsule" (Merck Veterinary Manual, Hoof Abscesses in Horses, read 2026-08-28).
In plain terms: pus under pressure inside a rigid box. That is why the pain is so severe and so sudden, and it is why an abscess can make a horse look, to an owner, as though something catastrophic has happened.
Laminitis. Merck: "laminitis is the inflammation and subsequent separation of the laminae of the hoof," and the manual describes it as "one of the most important and catastrophic diseases in horses," with outcomes ranging from "temporary loss of use to career-ending or life-threatening circumstances" (Merck Veterinary Manual, Laminitis in Horses, read 2026-08-28).
The laminae are the structures attaching the hoof capsule to the bone inside it. That is the whole reason this one is different in kind rather than in degree.
What they share, which is the problem
Sudden onset. Both can go from a normal horse in the evening to a horse in obvious trouble in the morning.
Severe lameness. Merck describes acute onset of severe lameness in one limb for an abscess, and a stiff, short-strided gait for bilateral laminitis. Both are unmistakable to an owner as "something is badly wrong."
An increased digital pulse. Merck lists "an increased digital pulse or higher palpable temperature of the hoof capsule" among the abscess examination findings, and describes "a bounding, exaggerated digital pulse" as a hallmark of laminitis. This is the point people are most often misled on. A strong digital pulse tells you there is inflammation in that foot. It does not tell you which condition is causing it.
Heat in the hoof capsule. Same problem, same reason.
If you have never felt a normal digital pulse on your own horse, you cannot recognize an abnormal one. That is why we treat it as a daily-routine skill rather than an emergency one, in how to find and feel a digital pulse.
The one pattern that points
How many feet.
Merck's abscess description is "acute onset of severe lameness in one limb," and it names the abscess as "the most common reason for a non-weight-bearing lameness in horses." One foot, dramatically.
Merck's laminitis description is that "usually, both forefeet are affected; however, any combination of affected limbs is possible," and that the horse with bilateral forelimb involvement shows "an extremely stiff, short-strided gait in which the forelimbs are placed in front of their normal position and the hindlimbs are placed under the horse."
So the pattern is: one foot, will not put it down leans abscess. Both front feet, rocked back, reluctant to walk at all leans laminitis.
Now read Merck's own caveat again: "any combination of affected limbs is possible." Laminitis in one foot happens. An abscess in two feet at once happens. The pattern points; it does not decide, and an owner using it to decide not to call is using it exactly wrong.
What to tell your vet on the phone
Have these ready. They are what turns a call into a triage.
- Which feet, and how many. Watch him stand and watch him take three steps if he will.
- How he is standing. Rocked back with the front feet out in front? Shifting weight from one front foot to the other? Refusing to put one foot down at all?
- Whether he will move, and what it looks like when he does.
- The digital pulse on each of the four feet, compared with each other.
- Heat, felt at the coronet and the wall, on each foot.
- When it started, and what he was like the last time you saw him.
- What has changed recently. New grass, a feed change, a recent illness, a long trailer journey, a course of medication, a change of work, a rich pasture after rain. Your vet will ask, and the answer sometimes matters more than the foot does.
- His vital signs, if you can take them safely. Our guide is how to take a horse's vital signs, and his own baseline is what makes the numbers mean anything, which is the argument in your horse's baseline.
What not to do while you wait
Do not move him more than you must. Ask on the phone where the vet wants him and how to get him there. If he is on a hard surface and cannot walk, say so and ask.
Do not give him anything. Not a painkiller from the cupboard, not a leftover from another horse, not a supplement. Pain medication changes what the vet finds and can change what they can safely give.
Do not soak, poultice or wrap the foot on your own initiative. Merck notes that "soaking the foot and pain medication are standard treatments" for an abscess, and that is exactly why it must be a veterinary instruction: it is a treatment for one of the two conditions and you do not know which one you have.
Do not dig at the sole, pare the foot or try to find the abscess. Merck describes the treatment goal as establishing drainage, with a veterinarian typically creating a small opening while preserving healthy horn: "creation of ventral drainage with sole debridement should markedly improve a horse's lameness." That is a procedure, not a hoof-pick job.
Do not turn him out onto grass to "keep him moving." If this is laminitis, the pasture may be part of the cause and the movement may be part of the damage. Ask.
Why you assume the worse
If you are wrong about an abscess and treat it as laminitis, you have called a vet out for something that was going to resolve with professional drainage and time.
If you are wrong the other way, you have spent hours or days on a condition Merck describes as one of the most catastrophic in horses, in which the structures holding the hoof capsule to the bone are separating, and where the outcome can be career-ending or life-threatening.
Those two errors do not cost the same, and that asymmetry is the entire argument of this page.
FAQ
How can I tell if my horse has an abscess or laminitis?
You cannot, reliably, and neither can this page. The pattern that points is the number of feet: Merck describes an abscess as acute severe lameness in one limb and the most common reason for non-weight-bearing lameness, while in laminitis usually both forefeet are affected and the horse stands rocked back. Merck also notes that any combination of limbs is possible in laminitis, which is why this points rather than decides.
Does a strong digital pulse mean laminitis?
No. Merck lists an increased digital pulse among the examination findings for a hoof abscess and describes a bounding digital pulse as a hallmark of laminitis. It tells you there is inflammation in that foot, not which condition is causing it.
My horse is three-legged lame overnight. What do I do?
Call your veterinarian now, keep him still, give him nothing, and gather the information listed above for the call. Merck describes non-weight-bearing lameness as most commonly an abscess, but "most commonly" is not "always" and this is not a wait-and-see situation.
Should I soak the foot?
Only if your vet tells you to. Merck names soaking among the standard treatments for an abscess, which is precisely why it is not something to start before you know which condition you are dealing with.
Can I give bute while I wait for the vet?
No. Do not give any medication before the vet has seen the horse or told you to. It changes the examination and it can affect what they are able to do next.
Is laminitis always in both front feet?
No. Merck says usually both forefeet are affected but that any combination of affected limbs is possible. That sentence is the reason the one-foot-versus-two rule cannot be used to rule laminitis out.
Sources consulted: Merck Veterinary Manual, "Hoof Abscesses in Horses", read 2026-08-28, for the definition, the pressure mechanism, the most common reason for non-weight-bearing lameness, acute onset of severe lameness in one limb, the increased digital pulse and hoof temperature findings, the coronary band swelling, soaking and pain medication as standard treatments and the drainage description; Merck Veterinary Manual, "Laminitis in Horses", read 2026-08-28, for the definition, the catastrophic disease description, the stance, the bounding exaggerated digital pulse, and both forefeet usually being affected with any combination possible. This site is not written by a veterinarian or a farrier. Nothing on this page is a diagnosis, a dose, a soak, a poultice or a treatment instruction, and every finding described here has one action attached to it: call your vet.