Dear I.:
My son was also diagnosed with similar allergies which included all cheeses, barley and wheat! Of course, I was overwhelmed because his sister had a whole different bunch of allergies! It is very difficult at first but he's almost 11 years old now, she's almost 13 and this has become really easy! So be encouraged!
First of all, ask your pediatrician to order you a Rotation Diet Schedule based on your child's allergies. For example, if your child has immediate hypersensitivity reaction to peanuts, you may never give this food to your child...never. But if your child has delayed hypersensitivity to other foods, say eggs, your schedule will tell you to eliminate them (for example) for 9 months and then reintroduce them one time per week. (The schedule spells it out for you to make it easier.)
Once you begin reintroduction, you carefully watch to see if the child exhibits any of the following: joint pain, headaches, hyperactivity, listlessness, vomiting, extreme gassiness or the return of the eczema. If you see any of these things, you need to eliminate the food again. (You also have to be careful because some of the delayed allergies could become immediate.)
I was overly cautious so I doubled the time of all the eliminations and when I reintroduced, we found that most of the allergies had been eliminated with the obvious exceptions of peanuts and almonds. We can live with that!
For your child, combat his constipation with plenty of fruits and vegetables. During the summer, make him some smoothies (you can use ice water or juice) with berries, mangos, or peaches and add grains such as boiled oats or ground flaxseed. Grind it all up with ice and he'll love it! For added healthy fat, add Udo's Oil to the smoothie and he'll never notice. If he's used to sweeteners, you can use agave syrup or honey. This should keep him going regularly.
As far as adding fats, an easy way is to use something they love. For some reason, kids love dipping things before they eat so how about a bowl of olive oil and some homemade bread, steamed broccoli, or steamed zucchini strips? Avocado is a good fat and so is salmon. My kids have always flipped out over salmon and brown rice all mixed together with olive oil sprinkled on top.
Just remember a trick I've always used. Every week, when I shop for groceries, I pick up a different vegetable and a different fruit (chives and tomato, watercress and pear, bell pepper and kiwi, cilantro and apricot, artichoke and banana, etc.) and keep the variety going. This will reduce the chance of any new allergies springing up (this sometimes happens if you eat too much of a single food) and it'll open up your options so your child has plenty of choices and balanced nutrition.
This may seem difficult at first but you'll see that ultimately, it'll benefit your entire family!
Best wishes,
M.
PS: If you're still nursing, you need to eliminate these foods in YOUR diet, too! Especially the peanuts!