Skin Conditions, General | September 22, 2015 | Author: The Super Pharmacist
The use of leeches in medical treatment has a rich history spanning over 3000 years, with the practice of bloodletting (the withdrawal of blood from a patient to cure or prevent illness or disease) being used by a wide range of practitioners for a diverse range of ailments. It was first used by the ancient Egyptians, Greeks and Romans, and reached its peak use globally during the 19th Century after spreading through Europe following the Renaissance. Leeches have been used as treatment in a variety of different medical theories. In 2300 BC, physicians and philosophers considered all illness to be the result of an imbalance between the four ‘humors’ in the body (blood, phlegm, black bile, and yellow bile). Bloodletting was considered the most suitable option for restoring balance. Up until the 17th Century, a wide range of practitioners also used the application of leeches in the belief that they were the optimal medical treatment for fevers and various organ inflammation (1). In modern day medicine leeches are rarely used as a treatment option for any form of illness, although some regulatory bodies, such as the FDA in the US, have approved their use (2).
Leech therapy has established itself as an alternative therapy for the treatment of a range of illnesses, including cardiovascular disease, hypertension, varicose veins, haemorrhoids, and ischemia-related dermatosis (3). Its use has also been trialled in the treatment of various cancers, diabetes mellitus and a number of infectious diseases, but there are no clinical trial results that support their use and no indication that they have been beneficial in treating any of these illnesses. There are also reports of its use in dentistry to treat traumatic and postoperative macroglossia (swelling of the tongue), as well as gum disease and abscesses. Its use in treating a number of skin conditions such as eczema and shingles has also been documented, but there is no evidence to support their use in helping to cure or alleviate the symptoms associated with these diseases. The earliest known research in regards to leech treatment was conducted by a French physician named Dr Pierre Louis in the 1850s. In one of the first examples of clinical epidemiological research, he examined the histories of 77 of his patients that had been treated with bloodletting techniques. The study concluded that the procedure ‘was much less effective than commonly believed’ (4) and was the catalyst for increasingly widespread levels of scepticism regarding its viability as a medical treatment. There is some documenting of the use of leeches for a number of conditions such as haemochromatosis (a hereditary disease characterised by excessive levels of iron in the body), polycthaemia vera (a high concentration of red blood cells that makes it difficult for blood to travel through vessels and organs), and porphyria cutanea tarda (an enzyme deficiency condition that is characterised by excessive blistering) (5). However, there is no evidence to support their use for these particular conditions. Modern day bloodletting (typically referred to as therapeutic or serial phlebotomy) is now conducted intravenously with a needle. What had initially started out as traditional treatment has evolved into an evidence-based medicine, with replicable studies showing that serial phlebotomy plays a significant role in alleviating the symptoms and complications of diseases such as haemochromatosis through removing excess iron stores (6,7,8). Some commentators suggest that the leech still has a role to play in the treatment of particular conditions due to their ability to reduce venous congestion and prevent tissue necrosis. As such, their use has been advocated for in the postoperative care of skin grafts and reimplanted fingers, ears and toes, but there is no evidence for this assertion. In response to concerns around secondary infection caused by the use of leeches, some researchers have developed a ‘mechanical leech’ to mimic the effects of a leach, but it has never been used in any form of clinical treatment (9). Despite the safety concerns that exist around the uses of leeches, they are still used in some parts of the world as both a complementary and mainstream treatment. Practitioners often cite the presence of an anticoagulant agent in leech saliva called hirudin as the main reason for its use, and its role in treating a range of illnesses such as migraines, arthritis, and a number of vascular diseases (10). There is a limited evidence base investigating the use of leeches as an analgesic in the treatment of chronic arthritis, with a number of studies advocating for their use as a natural alternative to OTC pain relief. A single study claimed that leech treatment was more effective than topical diclofenac in relieving pain experienced by arthritic patients, but the study displays significant bias, doesn’t take into account a wide range of confounding variables, and relies solely on qualitative data from a small study sample making the results less meaningful(11).
It is widely understood that infections are a common side effect of leech related bloodletting, with studies estimating approximately 36% of patients undergoing treatment are affected (12). A number of bacterial strains have been found in leech related infection, and certain strains such as "Aeromonas hydrophila can cause pneumonia, mascular necrosis (the death of bone tissue due to inadequate blood supply), and, in some rare cases, septicaemia. Blood loss through prolonged haemorrhage, and scars left by the leeches themselves, are also well known side effects of treatment (13)". More tests are required to ascertain the viability of leech related treatment, although given the well developed field of serial phlebotomy treatment it is unclear at present what the particular purpose of leech treatment serves in modern medicine.