If you think your horse had strangled immediately quarantine them because it is super dangerous and contagious
rapid on-set of high temperature (39.5 to 40.5 degs),
loss of appetite,
discharge of yellow pus from the nose,
symmetrically enlarged glands of the head and neck that often form abscesses,
Strangles is very serious and extremely contagious, if you suspect you have a case call your vet ASAP!
Im pretty sure strangles is a lump on the bottom of their head but I know that the symptoms can range from high temperature, loss of appetite, yellow puss from the nose, and they cough too. hope this helps!