Pressure sore ulceration (also known as bedsores) on a patient's right heel. Pressure sores are ulcers that develop on the skin of bedridden, unconscious or generally immobile patients. The sores start as red painful areas that become purple before the skin breaks down into open sores. Once open, the sore can become infected, enlarged and deeper. Deep, chronic sores may require treatment with antibiotic drugs, packing with plastic foam and possibly plastic surgery.