Skin infections are most commonly caused by bacteria, followed by mycosis and viral diseases. Most bacterial infections of the skin are caused by Staphylococcus aureus, streptococci and pseudomonads. Folliculitis is the inflammation of hair follicles, possibly leading to permanent hair loss. Impetigo and Ecthyma are inflammatory skin diseases characterised by pustules leaving scars and pigmentation, if untreated. Skin infections may interrupt the integrity of the skin, the natural defence barrier of the non-specific immune response , facilitating invasion of possible pathogens.
Diabetes can result in severe infections of the skin, i.e. diabetic gangrene.
Bone and joint infections include most commonly septic arthritis and osteomyelitis, caused by pathogens such as Staphylococcus aureus. Inflammation of the bone is painful and may lead to the formation of abscesses.