Is allergy testing necessary to treat the cause of eczema? i've heard a lot mentioned regarding knowing what a persons allergies are.

Usually not: Depends on the age. In infants and toddlers, food allergies can often play a role, so testing can be helpful. In older kids and adults, it does not always help identify triggers. But it can still be helpful - i find dust mite allergy seems to correlate to eczema. Plus, often patients with eczema have other issues (sinus, respiratory) that allergy testing can help identify.