a cluster of boils, draining pus onto the skin. It is usually caused by bacterial infection, most commonly with Staphylococcus aureusorStreptococcus pyogenes, which can turn lethal. However, the presence of a carbuncle is actually a sign that the immune system is working.[1] The infection is contagious and may spread to other areas of the body, or other people; those living in the same residence may develop carbuncles at the same time. The phenotype is EFO_1000674 (carbuncle).