Thank you for your question.
Diet wise, when it comes to allergies, I will always recommend a hydrolysed diet. This is a diet whereby all of the proteins have been broken down so, whatever the dog is allergic to, they won't react. The most common food allergies are dairy, egg, chicken, beef, peas and grains.
There are 3 main hydrolysed diets in the UK: Royal Canin Anallergenic, Hills z/d or Purina HA.
You feed one of these for 8 weeks and be sure to not give any other foods, treats or chews.
The hope is that by the time the 8 weeks is up, the signs have much reduced or even gone.
Raw diets... I'm not a big fan.
Firstly, if he has an allergy to e.g. chicken or beef, feeding a raw diet with one of these ingredients won't help.
Also, raw food poses a health hazard to dogs and humans alike. Children, the elderly and those who are immune-suppressed are most at risk. If your dog eats his meal and then e.g. licks your face, there is a real risk of food poisoning.