During systemic diseases, various cutaneous lesions can arise. When the diagnosis of the disease is known, it is quite easy to attribute the cutaneous symptoms to this disease. But, when confronted to a child with a rash and fever infectious disease has to be excluded first. If the antiinfectious treatment is not effective, a systemic disease can be suspected. Acute systemic disease may present as malaise, fever and cutaneous lesions, without specific biological abnormalities. The cutaneous symptoms can then be precious in reaching the correct diagnosis.