Whatever the source of the stress, it's translated pretty much the same to the body when allergy is concerned. The symptoms are pretty much common. One added factor is that some bodies are more susceptible to symptoms and insults to the body than are others. The difference in the degree of manifestation of the symptoms lies in the body's translation of the stress, as stress causes the release of glucocorticoids which tear the immune system to shreds. That goes for people too, for instance.
Personality is involved.
What appears as an insurmountable mountain to some, is only perceived as a mole hill to another. Healthy cells can prevent harmful substances from entering them, but lack of nutrients increases cell permeability, allowing the cell less control over what goes in or out. Consequently, the body becomes more susceptible to the effects of foreign substances and toxins in the environment, which can now enter more easily. Foods that remain incompletely digested can act as a foreign irritant. Even many harmless by-products of digestion can also be acted upon by putrifactive bacteria in the intestine to produce toxic and allergenic substances.