Medicines for Pyoderma gangrenosum

What it is

Pyoderma gangrenosum (PG) is a rare skin condition that causes painful ulcers (open sores) to develop, often quite rapidly. Despite its name, it is not caused by an infection ("pyoderma") or by gangrene — it is thought to be related to a problem with the immune system, in which the immune system causes inflammation that damages the skin. PG typically starts as a small red or purplish spot, pustule, or blister — sometimes at the site of a minor injury — which then breaks down and enlarges, often quickly, into a painful ulcer with a characteristic bluish or purplish, overhanging edge; the ulcers can grow, be very painful, and may occur singly or as several, most commonly on the legs but potentially anywhere. PG can be associated with other conditions in many cases — particularly inflammatory conditions such as inflammatory bowel disease (Crohn’s disease or ulcerative colitis), some forms of arthritis, and certain blood or other conditions — though it can also occur on its own. A very important point about PG is that it is often initially mistaken for an infection or a simple wound, and — crucially — it can be made worse by surgery or injury to the area (a phenomenon called "pathergy", where trauma triggers or worsens the condition), so operating on or aggressively debriding the ulcers (as might be done for an infected wound) can worsen it. This is why correct diagnosis is important, and why PG is treated primarily with medicines that calm the immune system and reduce the inflammation, rather than surgery. Because it can be misdiagnosed, and because it needs specific treatment, a rapidly enlarging, very painful skin ulcer that is not behaving like a typical infected wound should be assessed by a doctor, ideally including a dermatologist. With appropriate treatment, PG can be controlled and the ulcers healed, though it can be a challenging and sometimes recurrent condition. The key messages are that pyoderma gangrenosum is a rare condition causing rapidly enlarging, painful skin ulcers (often linked to inflammatory conditions), that it is not an infection and can be worsened by surgery, and that it is treated with immune-calming medicines — so prompt, correct diagnosis matters.

How it is treated

Pyoderma gangrenosum is diagnosed and treated by specialists (dermatologists, often with input from other specialists), with the mainstay being medicines that calm the immune system and reduce inflammation, along with careful wound care and treating any associated condition — and, importantly, avoiding surgery to the ulcers where possible. Because PG can be mistaken for an infection or a simple wound, and because it needs specific treatment, correct diagnosis is important: it is often a "diagnosis of exclusion", made from the characteristic appearance and behaviour of the ulcers (rapidly enlarging, painful, with a bluish overhanging edge), the response to treatment, and by excluding other causes (such as infection or other causes of ulcers), sometimes with a biopsy and tests — assessment by a dermatologist is valuable. A crucial point in management is that PG can be worsened by trauma or surgery (pathergy), so aggressive surgical debridement or operating on the ulcers is generally avoided, as it can make them worse — this is a key reason correct diagnosis matters, to avoid inappropriate surgery. The mainstay of treatment is medicines that reduce the immune-driven inflammation: this often starts with steroids (corticosteroids), either applied to the skin or, for more significant disease, taken by mouth or given into a vein, and frequently alongside or followed by other medicines that calm the immune system (immunosuppressant or immune-modulating medicines), including, in some cases, targeted (biologic) treatments — the choice depends on the severity and the individual, and treatment aims to control the inflammation, stop the ulcers enlarging, and allow them to heal. Careful, gentle wound care (with appropriate dressings, and gentle rather than aggressive management) supports healing, and managing pain is important, as PG can be very painful. Treating any associated underlying condition (such as inflammatory bowel disease or arthritis) is also important, as controlling the associated condition can help the PG, and PG may be a sign of an underlying condition that needs assessment. PG can be a challenging condition, sometimes taking time to heal and sometimes recurring, so ongoing specialist care, monitoring, and support are part of management. The reassuring messages are that pyoderma gangrenosum, although rare and sometimes challenging, is treatable — with medicines that calm the immune system controlling the inflammation and allowing the ulcers to heal — that correct diagnosis is important (both to give the right treatment and to avoid surgery that could worsen it), and that treating any associated condition helps; so a rapidly enlarging, very painful skin ulcer that is not behaving like a typical wound should be assessed promptly, ideally by a dermatologist.