Noncompliance with hygiene guidelines is a major cause of complications after the therapy. Those may be bleedings, haemorrhage, infection. The last complication can occur as a result of scratching or soiling the wound.
Also the leech itself can be the source of infection if it’s not absolutely healthy and vital. Probable reason may also be the condition of patient’s skin, dirty clothes and other. The Aeromonas bacteria which is in symbiosis with hirudo medicinalis can cause possible complications if the patient’s immune system is weakened. If the patient suffers from gastric or duodenal ulcer, dangerous haemorrhage is possible. Applying the leech on a place with inadequate blood supply, ischaemia or necrosis may also result in severe complications.