My 6 month old grandson has a transient rah on his arms, legs and face. Nothing on his trunk. The rash looks like a mosquito bite - ie, raised central area with an outer red area. The condition does not seem to be bothering him - not distressed, no temp, not itchy. Normal happy self. These spots seem to disappear and reappear over a very short interval (a couple of minutes). This began about 36hrs ago. He is on no treatment. Any help/suggestions would be appreciated. Thanks, Dan