Ann,
  Taking this baby off the breast may not only be unnecessary, it may be the
worst thing to do.  My second child developed eczema at 6 weeks and his
Pediatrician prescribed a topical cream and oral steroids.  I did not give the
oral steroids but took a look at my diet instead.  It was February in Florida,
peak orange juice season and I was consuming more than a quart of fresh
squeezed juice daily. I deleted the OJ from my diet and his rash improved
rapidly.
       Sad to say my baby with eczema (as well as my next son) went on to
develop asthma despite years of breastfeeding and doing "all the right
things."  The only consolation is that they were both well into their third
year when symptoms began and that the asthma is not as severe as it might have
been if they had not been breastfed.
      I suspect there is a history of allergy in this family and that the
mother would be wise to eliminate the foods which commonly cause allergic
response and continue nursing. It certainly is worth a try. This baby's rash
might appear to improve on the "special" formula for a short time but the long
term risk to his health is a great price to pay.
     I hope her visit with the Dermatologist goes well. You can bet he (or
she) likely knows everything about rashes and little about breastfeeding. Glad
she has you to encourage her and protect this baby's health.

Nancy Imperiale, RNC, IBCLC
Dunedin, FL