Insect sting allergy potentially something very serious and can lead to anaphylaxis, which is potentially life-threatening. The majority of individuals who receive a sting from an insect experience local reactions. It is estimated that 5-10% of individuals will experience a generalized systemic reaction that can involve symptoms ranging from hives to wheezing and even anaphylaxis. In the United States approximately 40 people die each year from anaphylaxis due to stinging insect allergy. Potentially life-threatening reactions occur in 3% of adults and 0.4–0.8% of children. A 2012 meta-analysis found that venom immunotherapy is an effective prophylactic treatment against insect bite and sting allergic reactions,
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