Allergic Rhinitis and Enzyme Potentiated Desensitization

Enzyme Potentiated Desensitization (EPD) is an alternative form of conventional immunotherapy (also known as allergy shots). It was originally popularized in the UK in the 1960s by a man named Leonard McEwan. It involves the injection of very low levels of an allergen, combined with the naturally occurring enzyme beta glucuronidase. EPD proponents claim that this method heals allergy problems, including allergic rhinitis. Proponents say that EPD can successfully treat hundreds of medical conditions, from rheumatoid arthritis to epilepsy. The evidence used to support these assertions is limited. However, because EPD is probably harmless, it might be worth trying.

A similar and more widely accepted treatment for allergic rhinitis is sublingual immunotherapy (SLIT).

Proponents of EPD claim that this treatment gets to the root of allergy problems by "retraining" the immune system to not over-respond to harmless substances that otherwise cause allergic reactions.

Read more details about Enzyme Potentiated Desensitization.

Proponents of EPD are very enthusiastic about its usefulness in treating allergy-related conditions such as allergic rhinitis, but research evidence is weak.

In the first double-blind, placebo-controlled study, 183 people with a history of consistent hay fever were treated with EPD or placebo and followed throughout the hay fever season.³³ The EPD preparation contained beta glucuronidase, 1,3-cyclohexanediol, protamine sulphate, and a mixed extract of allergens, including pollens, fungal spores, cat and dog danders and dust mite. The fake treatment contained only saline. Neither the researchers administrating the injections nor the study participants knew which was which. Both groups improved markedly. However, there was no difference in symptoms between the two groups, as measured by problem-free days, quality of life scores or symptom severity scores.

A slightly smaller study did find benefits. In this double-blind study of 125 children, use of a single dose of EPD reduced hay fever and asthma symptoms as compared to placebo.³⁴

Safety Issues

Whether or not EPD is effective, it does appear to be safe. No serious adverse reactions have been associated with its use. Although in theory allergic reactions could occur in response to EPD injections, the amount of allergen used in EPD is so much lower than the amount used in a normal "allergy shot" that these may not, in fact, occur.

EPD proponents claim that there can be a temporary aggravation response that is part of the healing process; however, this has not been documented.

33. Radcliffe MJ, Lewith GT, Turner RG, et al. Enzyme potentiated desensitisation in treatment of seasonal allergic rhinitis: double blind randomised controlled study. BMJ. 2003;327:251-254.
34. Galli E, Bassi MS, Mora E, et al. A double-blind randomized placebo-controlled trial with short-term beta-glucuronidase therapy in children with chronic rhinoconjunctivitis and/or asthma due to dust mite allergy. J Investig Allergol Clin Immunol. 2006;16:345-50.