I am highly allergic to propylene glycol and polyethylene glycol. I am finding many hidden sources of both and MANY synonyms for PG and PEG. Is there a practical way to tell how closely related another chemical might be to my allergens using such resources as the U.S. Household Products data base? For example: glycerin's alternate name is propandiol. Propandiol is also an alternate name for propylene glycol. I'm very confused about sodium laureth sulfate in particular. It has PEG listed as an alternate name, but is not an alcohol like the glycols. Thank you for any clarification you can give me!
You'll probably be better served asking an allergist about this.
While many things contain PG, that is not the same as a compound similar to PG, which could have PG (or part of its IUPAC name, propane-1,2-diol, not to be confused with propane-1,3-diol, which would be its possibly harmless-to-you although structurally similar isomer) as part of its name or could interact with your body in a similar way. Case in point, your confusion over sodium laureth sulfate, which is nothing like PG, although that's an irritant for everybody. However, it looks like PG allergy is sometimes co-sensitized with corticosteroids - which are themselves structurally nothing like PG!
Thus, the confounding variable here is the way your body decides what will or will not set off your immune system, which can have very little to do with the chemical behavior of the allergen and everything to do with what mechanisms your body is using to make that distinction.