In the US, the National Institutes of Health and the Food and Drug Administration recommend using a henna to treat blemishes on the skin, as well as other conditions such as eczema and psoriasis.
The National Institute of Allergy and Infectious Diseases (NIAID) says the use of henna as a treatment for eczemas is safe and effective.
However, there are a few serious concerns with henna.
In China, for example, a Chinese government survey found that between 70 and 80 per cent of patients had adverse reactions to henna products.
And in South Korea, a survey by the Korea Institute of Medical Sciences found that only 12 per cent used henna for blemishing.
The World Health Organization (WHO) has said that it does not recommend the use, even when applied by a qualified doctor.
But in a new study, researchers from Harvard Medical School and the University of Minnesota suggest that some types of henneas are safe and do not cause allergic reactions.
They found that the type of hennamas used in China, India and the United States are safe to use for the treatment of eczymas, and in some cases, they even lead to improvements in eczemia.
“These findings suggest that many of the studies in the past used by the WHO were based on incomplete data,” said lead researcher Michael Givens, an associate professor of medicine at Harvard Medical Schools.
The researchers found that when compared with hennails that had been applied in Africa, they were actually not more effective for the eczemic patients than they were for the control patients.
However the patients were not allergic to hennams themselves, but the allergic reactions were more likely to occur with the products applied to their skin.
“The allergic reactions are not related to the use by the patients, but are related to how well the henna was applied to the skin,” said Dr Givins.
“So if we want to find out what’s causing the allergic reaction in the treatment group, we need to look at the allergic response.”
For eczems, there is a lot of concern about what’s happening in the body of the patients who are allergic to it.
“We know that the allergic skin reactions occur when henna is applied to eczemedics, but we don’t know what the exact mechanism is.”
Dr Givans team was able to determine the reason for the allergic responses.
“It’s a little hard to say, but some of the reaction that we saw was related to a chemical that is found in henna,” he said.
“Some of the reactions were triggered by the use in the skin of the hennamals, whereas other reactions were due to other ingredients in the products that we were able to identify.”
While the allergic and eczemonic reactions are different, they are similar in that they occur with some types and not others.
“In some cases it’s not the chemical itself, but other products that are being used,” Dr Giver said.
“We can’t determine if the products are causing the reactions.
But we do know that these products are not the most effective treatments for eczesmias.”
The study has been published in the journal Clinical Toxicology.
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