Latex allergy allergy is an IgE (immune) mediated reaction to proteins found in the "Hevea brasiliensis" tree, a type of rubber tree. Testing for type I natural rubber latex allergy is through blood testing to determine if the patient is producing IgE antibodies to latex proteins. Anaphylactic shock can be provoked in allergic persons by the "previous" use of latex in an area: latex is typically powdered to prevent sticking, latex proteins become attached to the particles of powder, and the powder becomes airborne when the latex item is used, triggering potentially life-threatening Type I reactions when the latex-contaminated powder is inhaled
Henna a person has had a black henna tattoo and later dyes their hair with chemical hair dye, the allergic reaction may be life-threatening and require hospitalization. Because of the epidemic of PPD allergic reactions, chemical hair dye products now post warnings on the labels: "Temporary black henna tattoos may increase your risk of allergy. Do not colour your hair if: ... – you have experienced a reaction to a temporary black henna tattoo in the past." PPD is illegal for use on skin in western countries, though enforcement is difficult. Physicians have urged governments to legislate against black henna because