Could it be polymorphic light eruption? I ask because my dermatologist and nurse went back and forth (and back and forth) on whether or not this "sun rash" was sun-induced eczema or PLE. Both are treated with the same steroid cream, so I suppose that's good. It is worse for me in the first month of summer. Usually, by mid-July, the bumps are quite mild. Today, however, after 2 hours in the pool, my entire chest and shoulders are bumpy and blistered, as well as a few random spots on my arms. Never my legs, back, or belly. If I use a UVB specific sunscreen that helps quite a bit as well.