Pyoderma gangrenous (PG) is an extremely rare skin condition characterised by painful sores on the surface of the skin, commonly found on the leg. Only 3-10 cases per million population are thought to occur. Although the exact cause of this skin disease is not yet known, it is believed that a dysfunctional immune response is the root of the cause.

Individuals suffering from inflammatory conditions such as inflammatory bowel disease (IBS), Crohn’s disease, ulcerative colitis and arthritis are at an increased risk of developing PG. Thus in these people treating the underlying condition is the primary form of treatment. PG comes into the category of neutrophil dermatoses where the affected tissue contains a high percentage of the immune cells known as neutrophils.

Diagnosed usually using blood tests and swabs and cultures of the ulcer, this disease spreads fairly rapidly across the skin. The ulcers can usually be treated and disappear, however scarring and recurrences are common.

Types of Pyoderma Gangrenosum

• Classical PG- This is the most common type of PG where a small pustule/nodule rapidly forms into an ulcer. The ulcer has a raised border and a boggy, necrotic base. Usually this type of PG occurs on the lower legs or trunk and leaves scarring upon healing.

• Peristomal PG- This type of PG occurs around stoma sites and occurs mostly in IBS patients.

• Vegetative PG- This is typically less severe than the classical PG and occurs in healthy patients. It presents clinically as a single lesion which can be cleared quickly with topical treatment. Vegetative PG occurs mostly on the head and neck.

• Bullous PG- This type of PG presents as painful bullies areas that spread rapidly to form ulcers. It occurs mostly on the face and upper limbs.

• Pustular PG- This type of PG presents as sterile pustules that accompany fever. It occurs typically in those suffering from IBS and improves when the symptoms of IBS improve.

• Genital PG- This type of PG typically forms on the vulva, penis or scrotum.

• Extracutaneous neutrophilic disease- This types of PG usually forms on the lungs. It is slightly more difficult to treat as the lesions are located internally.