The treatment of haemorrhoids is generally free of complications. The following complications may nevertheless occasionally occur as a result of the disease itself or in association with the treatment:
bleeding from the anus as a result of damage to the rectal mucosa
formation of fissures and fistulae in the anal and rectal region (see link)
development of a contact allergy as a result of use of topical haemorrhoid products with sensitisation to the ingredients
occurrence of irritant anal eczema as a result of frequent use of substances and measures that irritate the skin (e.g. washing with soap)
anal venous thromboses may develop after sclerotherapy (see link)
anal prolapse may occur with longstanding haemorrhoids (see link)