In my 10 years experience as a natural skin care specialist I've learned a lot such as: the effects of essential oils & pregnancy, 'kills 99% of germs' isn't a good thing, and there is an increase in people presenting with sensitive skin.
It doesn't surprise me that someone presented with an allergic reaction to oats after using a product that contained oats because I've also learned we can build up critical mass to certain ingredients - and this differs from person to person.
One reason cosmetic conglomerates use petroleum and mineral oil based ingredients is because it is a cheap alternative to offer to those who have nut allergies, and therefore cannot use products that contain nut oils (i.e. almond, shea, walnut and hazlenut oils). There are other alternatives such as apricot and jojoba oil, both of which cost more to use.
One thing that concerned me about this article is it targets 'natural' skin care and products containing foods - which certainly maybe a concern for some, and ignores the elephant in the room. Which is far more people present with allergies and reactions to the ingredients in mainstream skin care. In fact it is quiet prevalent and common in today's society than ever before because of the amount of products we consume and the frequency in which we use them. Plus the vast amount of known 'skin irritation' causing ingredients in them.
By all means be mindful of anything that may give you an allergic reaction and STOP using any product (cleaning agent, hair dye, makeup, skin care, oils, grease etc) that cause a skin reaction such as urinary tract infection, psoriasis, eczema or contact dermatitis.
Find the products that are right for you but don't be scared to try natural skin care and see if it's a good fit.