The difference between allergy and intolerance?

[My little Liam]

I am pretty sure DS has an allergy/intolerance to dairy and eggs. I am Bf and from about 2 months old he had horrible eczema on his face and mucusy stools. The moment I stopped eating dairy it was 90% better. I didn't realize at the time that he might have more allergies and that is why it didn't completely disappear. Now that he is 10 months old and trying different foods we have bee getting a reaction to eggs. I have given him meatballs that had egg yolk cooking in them and we had bad diaper rash that looked like burns with little pimples for 4 days... A few weeks later I gave him a few bites of bread that I was eating not thinking about that fact that it was a special bread made with eggs and again the same diaper rash.
I haven't tried an egg or egg yolk by itself yet and we haven't tried any type of dairy yet.

When he was 7 months old I tried eating dairy again to see if he would react through the BM and I didn't really notice anything until theist month. He was sick for a few weeks but when he finally got better he still had this constant runny nose and cough. I started to think that it might have to do with all expiry I was consuming and three days after I stopped the runny nose was gone. Hubby seems to think it's a coincidence 
Anyways, it's driving me crazy that I don't know "for sure" if he is allergic to these things or not. We haven't been to an allergist and our pediatrician doesn't really take it seriously...

How do I know if it is an allergy or an intolerance? From what I understand he can't be tested for an intolerance, right?

I also feel lost regarding what I can feed him? At the moment he is on two meals a day, but I want to start him on three and I don't really know what to give him anymore. He is only now slowly starting finger foods and is still having a hard time chewing bigger pieces of food.  For breakfast he has 7 grain cereal with fruit and for lunch he usually has chicken with vegetables, sometimes I give him pasta too. Since I can't give eggs and I am worried about staring things like yogurt what else can I feed him? He isn't that great with chewing bread yet, and I don't really know what I could spread on it...

[We Three]

 I remember our doc telling us that a true allergy causes an immune system response, and has the potential for a more dangerous reaction, whereas an intolerance causes mainly gastro upset.  Its been a while for us, but I do recall being told that allergy testing isn't reliable in infants? Not sure on that.....but lots of Moms here have been through this, and will have good advice for you.  (((hugs)))

 From Mayo Clinic:

   http://www.mayoclinic.com/health/food-allergy/AN01109

[abbysmomma]

What pp said is true. Yours kind of sounds like an intolerance, but thatbeing said, you may not know for sure until he outright tries it. If it's an intolerance, i would just try every couple of months to see if he's outgrown it. Any hives or red marks on face? Vomiting? Unusual lethargy or tiredness up to two hours after ingestion? Trouble breathing, swollen face, itchy tongue etc. are all signs of allergy and you should see a pediatric allergist right away. My boys had terrible excema from birth but i didn't know what was causing it until they tried the allergen on their own ( i was breastfeeding). My boys have had allergy testing at your son's age, but since they're still developing, everything can change within a matter of months. Case in point, i had a scratch test for ds2 when he was 5 months and he was negative for everything. Three months later, he started reacting to egg, then peanuts. Hth and i'd ne happy to answer any other questions.

[My little Liam]

Like I said, as a newborn he had horrible pimple like eczema all over his face and ears. He was also extremely congested. When I stopped eating dairy it was so much better but he would still have small attacks now and the. I don't know if it was because he was allergic to something else too (eggs maybe) and I didn't realize it at the time or I wasn't reading every label and was missing some hidden dairy. There was never vomiting, trouble breathing or anything scary like that. Now that he is eating solids I am noticing the diaper rash from eggs, but I haven't given him dairy yet so I don't know. Do you think that through bf the reaction could be less severe than when eating the allergen? I thought he was handling me eating dairy much better since the eczema has nt come back for months but like I said we had the whoe runny nose situation and I have now been off dary again for about 10 days and no more runny nose...

Anyways, my husband and MIL have looked at me like I am crazy regarding the whole dairy situation but I just have this feeling in my gut and that is what is asking me even more scared for him to try anything...

[MasynSpencerElliotte]

I remember our doc telling us that a true allergy causes an immune system response, and has the potential for a more dangerous reaction, whereas an intolerance causes mainly gastro upset.  Its been a while for us, but I do recall being told that allergy testing isn't reliable in infants? Not sure on that.....but lots of Moms here have been through this, and will have good advice for you.  (((hugs)))

 From Mayo Clinic:

   http://www.mayoclinic.com/health/food-allergy/AN01109

Yes, Anne, that is right that intolerances are generally gastric upset and not hives and anaphylaxitic rxns. I think allergy testing under a year old is less reliable. We did it at around 18 months but it showed nothing. Our allergist considers her "allergic" to eggs based solely on rxns (she is now okay with egg baked in things, but not eggs themselves). She has intolerances to dairy, gluten and used to be to citrus fruits.

Another great site is:
http://www.kidswithfoodallergies.org