<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Pigmented purpuric eruption ? [/INST] What causes pigmented purpuric eruption? The cause of pigmented purpuric eruption is unknown. Occasionally, it occurs as a reaction to a medication, food additive, viral infection or following exercise. In rare cases, there appears to be a genetic component. </s>