People allergic to other people?

I have been told by allergists that it is impossible for a human to be allergic to another human. Is this true and if so why? I've seen old studies (done in the 1940s) on human dander and atopic dermititis, but nothing concerning typical
reactions such as sneezing, runny nose, etc.... Understandably, enviromental factors are usually pointed to as the source. If these can be ruled out over time (20+  years), what could be the cause of "allergic type" reactions to another person? Please Help!

[National Jewish Health]

I am only aware of a couple forms of allergy that human have developed to other humans.  One is the allergy to semen and the other allergy to immunoglobulin A (IgA) in individuals with an IgA deficiency.  Both result in anaphylaxis, a life-threatening event that cannot go unnoticed, often occurs immediately after exposure to the inciting agent, and generally results in a thorough investigation.  It is possible that a more insidious process with less obvious manifestations may go unrecognized.  The allergy to human dander is not such a process.  The allergic triggers in this instance are the droppings of the house dust mite, a component of that dander.

Bottom line is that being allergic to another individual is either non-existent or extremely rare.  However it is possible to be allergic to what the individual has applied to his/her body or is carrying on his/her body, for example cat dander or house dust mite.

[cursedtoo]

What exactly do you mean by " it is possible that a more insidious process with less obvious manifestations may go unrecognized."?
I have looked into TMAU (tested twice, both negative) and celiac disease, again negative. Could seborrheic dermatitis or GERD be involved? My breath is bad dispite immaculate oral care. I noticed these "allergic" type reactions shortly after puberty, could it be hormonal? This has been plagueing me for over 20 yrs....