advice please

My 5 month old baby has had this for around 2 months now. We haven't taken him to the doctors yet as we have been treating it as eczema. We used oilatum at first but no joy and then we tried aveeno and that seemed to work but it just won't go away completely. He also has it on his arms and shoulders and a little on his face too. It doesn't seem to bother him. Could it be eczema or a reaction to something like the laundry detergent we use?