Cysts are benign sacs that appear within or just below the skin. They most likely occur from a blocked pore or hair follicle, though some are probably hereditary. Epidermoid (or sebaceous) cysts may appear anywhere on the body, while pilar cysts typically appear on the scalp. The cysts are filled with a foul-smelling material that may occasionally drain from an overlying pore. Cysts may remain stable in size or enlarge over time, but they usually do not resolve completely on their own. If they are not painful, itchy, rapidly growing, or unsightly, they are benign and do not need to be removed. If bothersome, small cysts may be drained and removed with a small tool, however larger ones may need to be surgically excised.
If a cyst ruptures, it will become red, inflamed, swollen, and very painful. This may be the result of pressure, trauma to the area, or a bacterial infection in the cyst. In these cases, the cyst will most likely be anesthetized and drained, a simple procedure that brings immediate relief. Injected anti-inflammatories and oral antibiotics lead to quick resolution of symptoms.