We approach problems from a broad perspective that includes all reactions a person may have to the environment, with classical allergy as a possibility. It is important to know that various reactions to other substances and toxins are also plausible. What we breathe, drink, eat, and touch is part of our external environment, and all of it is highly relevant. Molds, mycotoxins, heavy metals, atypical infections, parasites, implants, drugs, fumes, chemicals, etc. are all issues to consider. Sophisticated testing for chemicals, heavy metals, and mycotoxins is available. Bodily fluids are often tested, and testing one’s home is also helpful in some cases.