Baby acne, food allergy or eczema?

She is just about 5 weeks old and for the past week and a half has been breaking out really bad. She always has a patch of little red bumps behind her ears and around her eyes but now her entire face is red and bumpy and some are whiteheads. Does this sound like normal acne or eczema? Or possible a food allergy. She is purely breast fed and I am trying to cut out dairy for 3 days to see if that helps.

Most likely it's the baby acne. Your hormones are starting to leave her system and this can cause break-outs. Make and appt. with her pediatrician to make sure, but most likely it's just the acne and will go away after a few weeks. Don't use soap, not even the baby bath kind on her skin, just wash her face gently with a soft cloth and plain water. And never touch or pick at the bumps. Good Luck.
P.S.- Don't cut out the dairy products unless her pediatrician thinks that's the cause, your body needs the calcium and protein of dairy products.

Sounds like baby acne to me. Consult your physician before cutting out dairy product.
There are many possibilites which you stated in your question.

A lot of babies at that age have baby acne that will just go away over time.

If that is not it, talk to your doctor about it. Explain your reasons for thinking it is eczema or a food allergy. They will help you out after that and may prescribe a cream to put on your baby.

My friends baby ended up being an allergy to egg (while she was only breastfed). They found out later when she was old enough to eat egg that she was severely allergic. Her mother loved eggs and ate them quite often. She was getting an allergic reaction through the breast milk. They thought is was eczema too.

Good luck!!!
i would make a list of what you eat and see if you can narrow it down that way
keep her clean and try the wash
it sounds liek baby acne and she will outgrow it
My daughter has had eczema since she was 3 moths old and she still has it she is now four years old. When she was younger there wasn't anything i could use or do for her because she was so young. Stopping the dairy and using soy milk is a good idea. Its definitely a skin allergy. Don't use anything on her skin that had perfume in it, that will irritate her skin. Everything that touches her has to be fragrance free. When you wash her clothes use something gentle like Dre ft. I used it and its wonderful. The new eczema was you can use a little bit not too much but the most important thing for her is no dairy and nothing with fragrance. Try it and see how it works. Its going to be frustrating but she will be OK. Good luck and god bless. ( You can also try, if her skin tends to get dry, aveeno baby lotion.)
My son had some baby acne on his chin and eczema on his eyelid that was dry and bothersome. I used Arbonne's Baby Wash and within two days it all cleared up. Their products are botanically based, no animal products or by-products, hypoallergenic, etc. They work wonders. I recommend to everyone, especially since some baby products actually contain hazardous chemicals in them. If you want more info, e-mail me. I use all their products and have some samples.
Mother of 3