Impetigo is not generally a serious problem. The sores that come from the infection are often mild and will heal without scarring. While complications are rare impetigo can cause the following: - Cellulitis can happen. This is a life-threatening infection that affects tissues under the skin and can spread to the lymph system. - Kidney problems are possible because the bacteria that cause impetigo can also damage the kidneys. - Scarring is a possibility.