In the early stages, the swelling is primarily a "pitting oedema"; in other words, if pressed, a depression remains in the skin of the limb.
In ulcerative lumphangitis, "cording" of the lymphatics and the formation of hard nodules and abscesses may also occur; occasionally, a greenish, malodorous discharge is present.
The mainstays of treatment are the administration of broad-spectrum antibiotics (typically potentiated sulfonamides or penicillin and streptomycin, but doxycycline may be the most effective).
Corticosteroids are sometimes used in severe cases, but should be used with caution due to their potential to weaken the immune response to infection, and the possibility of inducing laminitis.
Ideally, an abscess should only be lanced after it has matured well and has an obvious soft spot, or the procedure should be guided with ultrasound to find the best site for drainage that avoids important structures.
[5] Physical therapy is also important, particularly maintaining movement by walking out and massage to improve lymphatic drainage and reduce the oedema.
An overly tight bandage should not be applied, as swelling may continue, decreasing circulation through the limb, and potentially causing a bandage-bow.
In addition, once a horse has had an episode, it appears to be predisposed to recurrence, and may suffer from "filled legs" permanently – i.e. if left in a stable and relatively immobile, poor lymphatic circulation results in a passive oedema of the previously affected limb, that dissipates on exercise.