Consider histamine for example. This is a biogenic amine involved in the inflammatory response of the immune system especially with respect to allergens that bind to mast cells and trigger its release. A runny nose and water eyes are classic symptoms of an histamine-mediated allergic reaction.
There is also a Pictet-Spengler reaction here that might be expected to deactivate this biogenic amine in a fashion similar to that postulated for serotonin depletion in the gut:
See Acetaldehyde + serotonin //www.curezone.org/forums/fm.asp?i=1963129
However, acetaldehyde by itself is a potent stimulator of histamine release from mast cells:
See Kawano et al. http://www.ncbi.nlm.nih.gov/pubmed/15178893
and an inhibitor of the enzyme, diamine oxidase, that degrades histamine from its active form:
See Zimatkin et al. http://www.ncbi.nlm.nih.gov/pubmed/10344773
These factors may predominate in the case of histamine to create higher, rather than lower, levels of ambient histamine in conjunction with impaired pathways that are supposed to clear it once it has been released.
Histamine Intolerance is an acquired condition in which the body reacts to histamine in foods (e.g. red wine, soy sauce) also suggesting dysfunction of the pathways that dispose of this biogenic amine. Typical symptoms include headache, diarrhea, migraine, running or inflamed nasal passages, asthma bronchiale and arrhythmia, hypotension, urticaria and dysmenorrhoea.
See Maintz et al. http://www.ajcn.org/content/85/5/1185.full
Both doctors C.O. Truss (Missing Diagnosis, 1976) and W. G. Crook (The Yeast Connection, 1983) were allergy specialists before they began to focus on the interrelationship between yeast and disease. They found that many of their allergy patients responded to yeast reduction therapy, something that addresses the source of the toxin. The acetaldehyde-mediated disruption of histamine metabolism may be one of the mechanisms that increases an individual's sensitivity to allergy-prone substances.