Can henna be harmful for me?
A very small percentage of people can be actually allergic to henna, even if it is 100% natural. Symtoms of allergies include intense itching and wheezing, which will be very much similar to an asthma attack. If any such symptoms occur after the application of henna, wash the henna immediately, take the list of ingredients added to the henna paste and rush to your doctor.
Avoid henna if you have G6PD deficiency or you have been advised to stay away from Fava beans, or you are extremely anemic, or have citrus allergies. Consult your physician if you have any concerns or are pregnant and would like to use henna.
Some henna artists use coffee in their henna paste, this can give the client caffine jitters. Essential oils used in the henna, although natural, can cause irritation to some. The lemon juice applied after the application can cause allergic reaction to people who are sensitive to citrus and who have very thin and sensitive skin. Some companies add walnut powder to the henna powder, which can cause allergic reaction to people who are allergic to walnuts.
The best solution to avoid any such situation is to ask the list of ingredients used in the production of henna paste and to check whether you are allergic to it or not. In all cases, always stay away from black henna.