If your horse gets laminitis for whatever reason, is it then prone to get it from other factors i.e., the horse has a mechanical laminitis do you then have to be precautious about grass intake etc?
Having laminitis once doesn't mean that a horse is more likely to get it a second time provided that risk factors are controlled, in most cases by a good diet. The exception to this is cushingoid ponies.
However, once a horse has had laminitis the feet are permanently damaged to some degree, so any further bouts are more dangerous for the horse and less likely to end well.
So a horse that has had mechanical laminitis is no more predisposed to grass laminitis than his fieldmates of similar type, but were he to get it the disease could progress more quickly and be more serious, so best to keep an eye.