There is a strong history of atopy in the family. At this point infantile eczema is still a likely differential. The family history of dermatitis and the way you described the skin condition may still suggest that this is so. In infants the cheek seems to be the most common area involved. Infantile eczema may have variable appearances .They do not have a definite characteristic. So ,this is still a likely differential here.
I suggest you seek second opinion with another dermatologist .A pediatric dermatologist, if there is one in the area may be able to help. Psoriasis or seborrheic dermatitis are also differentials but psoriasis is rare in infants and young children.
My son (15 months) was diagnosed w/ Eczema early on, but nothing the doctor's (pediatrician, allergist, dermatologist) suggested/prescribed has helped much. I've always suspected it was something in his diet which triggered the outbreaks and found tomatoes and oranges made it worst. However, even after avoiding these, something would still set off his ezcema. What do these fruits have in common...Citric Acid! Than I realized so many things he'd consumed contained citric acid...it's everywhere, even in the medicine prescribed to control his itch (i.e. Hydroxyzine), which never appeared to help, but we figured it couldn't hurt, turns out it was making it worst! For the past few days, I've eliminated everything w/ citric acid, even his Aveeno Baby wash and Huggies shampoo and I'm already seeing a huge improvement. I don't know if this will help all babies, but it definitely is helping mine and this definitely won't hurt to try. I wish you the best of luck.