Eczema may be described as dry skin that may appear as raised spots which most typically affects the face and flexor surfaces (behind the knee and the fold in front of the elbow) of the body. Eczema is more common in children and may result due to hypersensitivities to food, harsh chemicals and other pollutants. The rash may by itchy and red. Psoriasis is rough, red and raised skin which may be itchy to. It may look as if there are silvery scales over the skin lesion. It usually affects the extensor surfaces (over the knee and elbow), trunk, lower back and hairline. Other symptoms may include nail pitting, and joint pain.
Your son's condition does sound more like eczema, but only a proper examination and history taking will be able to give an accurate diagnosis. Once you have a diagnosis I will be able to better guide you with diet, herbal medication and tissue salts. Please feel free to email me once he has been seen by a doctor
All the best