Adverse Reactions to Herbal Therapy in Dermatology

The use of herbal therapy by dermatology patients is on the rise. Because of their convenient availability, many patients with chronic dermatological diseases have attempted to take more control over their health by using herbal remedies along with or instead of conventional treatments. Some patients have lost hope; standard treatments have failed to be effective for them. As a result, they seek newer therapies in an attempt to find a "cure" for their problems.There are many herbal remedies that have scientific merit; they may be of clinical benefit and provide safe, effective and reliable alternatives to conventional medicine. However, herbal products cannot be patented. They are intended for the self-treatment of a self-diagnosed, selflimiting condition. Although there are numerous herbal therapies that are relevant to the specialty of dermatology, many of these have not been studied in proper randomized, double-blind, placebo controlled trials. Most herbal treatments have evidence that is based on sparse anecdotal reports and word of mouth.

Many of these therapies are considered "natural" and therefore harmless. However, because of the poor regulations that exist in monitoring these drugs, adverse reactions do occur. Herbal therapy, therefore, should be avoided in pregnancy, infants and children because of the uncertainty of adverse reactions that could occur. There is little incentive for pharmaceutical companies to investigate or standardize these preparations because it is unlikely patents would be applicable.

Because of the assumed safety of natural products, many patients believe these products have "fewer" side-effects. Herbal therapies should be regarded as drugs. Since drugs have side-effects, such events can be seen with herbals. Drug interactions although infrequent, can also occur with herbal therapies and conventional medications.

The most common dermatologic reaction from herbal therapies is allergic contact dermatitis. Herbs that are known for causing this condition include: aloe, arnica, bromelain, calendula, chamomile, goldenseal, tea tree oil and yarrow. However, more serious events have occurred including erythroderma and Stevens-Johnson syndrome from combination herbal preparations. Serious systemic adverse events have been reported with herbal therapies for the treatment of dermatological diseases as well. Most are hepatotoxic effects and some have been fatal although this is rare.Herbals that are recommended for topical use should not be ingested and vice-versa. Drug interactions that most commonly occur are due to immunomodulatory reactions, however effects on anticonvulsants and anticoagulants can occur.