The name says it all. Some people are sensitive to a range of agents, and on contact develop an intensely red itchy rash about 2 days later (delayed sensitivity). Common agents are metals (nickel,chrome), plants (grivilleas, primula, ivy, the Compositae family, tulip and daffodil), chemicals (petrochemicals, solvents, some detergents, antiperspirants, resins, formaldehyde, some cosmetics, preservatives and fragances in creams and lotions). Diagnosis can be much assisted by the use of Patch Tests on the skin. Avoidance is the chief management here.
An immediate burning rash (not that itchy, sometimes blistery) on contact is not an allergy but a light sensitivity to psoralen present in some plants: fig, lime, lemon, carrot, parsnip, parsley, and fennel. Naturally it occurs on exposed areas of the body.
PHOTO of boy’s face with eczema