Cellulitis is a bacterial infection of the dermis and subcutaneous tissues as stated previously. It is usually caused by Streptococcusor Staphylococcus aureus, but can also be caused by a wide range of other aerobic and anaerobic bacteria. A portal for bacterial entry will be present, such as a break or fissure of the skin, but this may not always be obvious or identifiable. Symptoms of cellulitis include (CREST 2005):