The concept of forbidden foods that should not be eaten goes back to the Garden of Eden and apart from its religious meanings it may also have foreshadowed the concept of foods that can provoke adverse reactions.

Thus we could say that allergic diseases have plagued mankind since the beginning of life on earth. The prophet Job was affected by a condition that following the rare symptoms described by the Holy Bible might be identified as a severe form of atopic dermatitis (AD).

The earliest record of an apparently allergic reaction is 2621 B.C.,when death from stinging insects was first described by hieroglyphics carved into the walls of the tomb of Pharaoh Menes depicting his death following the sting of a wasp.

In 79 a.d., the death of the Roman admiral Pliny the Elder was ascribed to the SO2-rich gases emanating from the eruption of Mount Vesuvius. Hippocrates (460–377 b.c.) was probably the first to describe how cow’s milk (CM) could cause gastric upset and hives, proposing dietetic measures including both treatment and prevention for CM allergy.

He also coined the term “asqma,”meaning breathlessness.Subsequently, Thucydides described that during the plague afflicting Athens from 430 to 429 b.c., “those people who recovered from the disease rarely developed the illness a second time and never mortally,” an observation that was verified by Panum in 1847.

The Roman poet Lucretius (98–55 b.c.) stated that “what is food to one, is a bitter poison to others.” Galen (129–202) was the first to describe allergy to goat’s milk and also evidenced the fifth cardinal sign of inflammation, that is the loss of function or functio laesa not previously described by Celsus (first century b.c.).

Perhaps an example of tolerance could be that of Mithridates (132–63 b.c.), who reportedly acquired immunity against poisons by assuming progressively increasing doses of each poison, a precursor of the oral desensitization by taking small incremental amounts of noxious foods.

The concept of immunity, deriving from the Latin immunitas (meaning being exempt from), a century ago was linked by early immunologists to the resistance of an individual to infections; therefore immunology probably began its march as acquired immunity.

The concepts of immunology have a long history and began primarily as a branch of microbiology. Fracastoro wrote in De contagione et contagiosis morbis, published in 1610, that “an infection is the same in both the carrier and newly infected” and postulated the existence of “imperceptible” germs.

Since then, several important discoveries have launched a renaissance of research into the field of immunology. Experimental immunology began in 1798 with Jenner, Pasteur developed killed and attenuated vaccines, and Miescher later discovered DNA (deoxyribonucleic acid).

In 1875 Cantani Sr stated that the cause of diabetes mellitus was to be sought in a missing ferment which in the healthy metabolized glucose.

He also demonstrated that dehydration should be cured by fluid rehydration. In 1890, Ehrlich expressed the concept of autoimmunity as horror autotoxicus, amply skimming the etiopathogenetic mechanisms.

At the turn of the century, von Pirquet coined the term “allergy” from “allos” and “ergos” (meaning altered reaction) and therefore included the development of protective immunity, coupled by Coca and Cooke in 1923 with the term “atopy,” from “atopos” (meaning out of place and thus abnormal); thus many episodes based on the mechanisms of cause and effect were brilliantly documented.

In 1921, Prausnitz and K├╝stner demonstrated the presence of “reagins” in the serum of allergic patients; in the same year a “Textbook of Immunology” was first published in Italy.

In 1966, the Ishizakas attributed a scientific meaning to reagins by identifying IgE as the carrier of reaginic activity in the sera of hay fever sufferers: the first case of immunodeficiency (ID) was reported in 1952.