Pyoderma gangrenosum is a rare condition that gives rise to painful ulceration and skin lesions, mostly on the legs. Although the cause of the disease is not correctly determined, it is considered to be autoimmune in nature. The patient may have an underlying disorder in most cases. The ulcers heal to a certain degree upon treatment, but scarring and recurrence can be expected.
What Is Pyoderma Gangrenosum?
Different from the name, pyoderma gangrenosum is neither an infection nor does it result in gangrene. It is considered to be an autoimmune disease, one of a group of inflammatory disorders known as ‘neutrophilic dermatoses.’ Ulceration lesions with undermined borders characterize it.
What Are the Causes?
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It is generally considered to be an autoimmune disorder with an idiopathic origin. It is believed to occur due to an exaggerated response to T lymphocyte or cytokine dysfunction. Autoimmune diseases are those that arise when the body’s immune system (which is designed to attack external stimuli) targets healthy tissues.
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One of the common causes is injury or trauma, a surgical wound may also trigger a response, but it is not to be confused with a wound infection. The formation of abnormal skin lesions at the site of injury is called pathergy.
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It may be associated with a genetic predisposition.
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Some drugs, such as Cocaine, Sunitinib, Propylthiouracil, and Isotretinoin, are sometimes considered to trigger the disorder.
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About 50 % of cases are associated with another systemic disorder such as inflammatory bowel disease or Crohn’s disease. It may also be associated with: myelogenous leukemia, rheumatoid arthritis, paraproteinemias, and myeloid metaplasia.
Who Are Affected?
It often occurs between the ages of 20 and 50, more commonly over 50. It affects women more than men. It is often associated with the following:
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Inflammatory bowel disease (long-standing inflammation of tissues of the digestive tract).
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Rheumatoid arthritis (a chronic inflammatory condition affecting the joints of the body). Monoclonal gammopathy (a condition characterized by the presence of abnormal proteins in the blood).
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Myeloid blood dyscrasias (low peripheral blood cell counts resulting from marrow failure).
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Chronic hepatitis (long-term infection with the hepatitis C virus).
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PAPA syndrome (pyogenic arthritis, pyoderma gangrenosum, and acne syndrome is a rare disorder resulting from mutations in the PSTPIP1 gene).
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Granulomatosis with polyangiitis (an uncommon disorder causing inflammation of the blood vessels in the nose, throat, sinuses, lungs and kidneys).
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Behcet disease (a rare disorder leading to inflammation of blood vessels in the body).
How to Identify Pyoderma Gangrenosum?
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Pyoderma gangrenosum starts as a small red bump or blister, which progresses into a large painful ulcer. It can occur in any part of the body but is commonly found in the legs.
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It starts as a minor injury, often mistaken for an insect bite or spider bite. It may appear as a small pustule or blister which breaks to form an ulcer. The ulcer can rapidly get deepened and broadened. The edges of the ulcer are purple and undermined. It is a painful condition.
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It may be found near a surgical site, and several ulcers may merge into one large ulcer.
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The ulcer may persist or enlarge or may spontaneously heal. Healing depends on the site and the presence of the underlying disorder. If treated, the ulcers stop enlarging, but complete recovery may take time.
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Ulcers may lead to scarring and often recur.
What Are the Types of Pyoderma Gangrenosum?
The subtypes of pyoderma are rare; they include:
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Bullous: Associated with hematological malignancy and presents with inflammatory blisters and ulcers.
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Pustular: Seen in patients with inflammatory bowel disease and presents with pustules (pus-filled lesions).
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Granulomatous Superficial (Vegetative): This variant is not associated with a systemic disease seen in the face and neck region. It presents with wart-like lesions and ulceration.
The classic pyoderma gangrenosum presents with a deep ulcer with a bluish-purple border, which is generally undermined. The surrounding skin may be red. Small patches or papules break down to form the ulcer, and several ulcers may join together to form a single ulcer with the central area, which is necrosed.
How to Diagnose?
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Clinical Features: It is diagnosed by its appearance and pain.
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Positive Pathergy Test: A skin prick test that causes a pustule (pus-filled raised area), papule, or ulcer.
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Blood Tests: May be done; some patients may have positive ANCA (antineutrophil cytoplasmic antibody).
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Culture: Swabs may be tested for microorganisms, although the lesions are not caused by an infection.
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Biopsy: May be done as a confirmatory test to rule out other causes for ulceration.
How to Treat Pyoderma Gangrenosum?
The treatment is done to promote healing and prevent further ulceration. A non-surgical approach is made. The necrotic tissue should be removed gently; care should be taken not to enlarge the borders of the ulcer. Wide debridement should strictly be avoided in active ulcers as it may cause the lesion to enlarge.
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Skin grafting may be done to promote healing after the active phase has passed.
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If there is a presence of secondary infection or if bacteria are found in the wound culture, antibiotics such as Flucloxacillin can be given. It may also be administered if the lesion has given rise to cellulitis. But for lesions that are not infected, antibiotics are not in use.
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Systemic treatment involves mainly steroid administration or any immunosuppressive regime, as it is an autoimmune disorder.
Small lesions are treated with the following:
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Topical steroid ointment.
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Steroid injections into the lesion- into the ulcer edge.
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Tacrolimus ointment.
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Cyclosporin solution.
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Doxycycline or Minocycline.
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Special dressings and compression bandages are also helpful; compression bandages help to reduce swelling but may cause pain.
Systemic treatment includes:
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Oral Prednisone (steroid) or intermittent intravenous administration of Methylprednisolone.
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Ciclosporin is as effective as Prednisone but has severe side effects.
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Infliximab, Adalimumab, and Etanercept, among others, have positive effects.
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Taking care of the wound is of utmost importance. Pain management is also a necessary step in treating the disease. After the primary treatment and the lesion begins to regress, skin graft, skin flap, cultured skin, and wound therapy are options that can be considered to repair the damaged skin.
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Systemic medications, mainly steroids, have to be slowly tapered; they should not be stopped abruptly.
How to Prevent Pyoderma Gangrenosum?
It can not be prevented entirely, but once the condition is diagnosed, care can be taken to avoid triggers to prevent further lesions. Any trauma or injury may promote the formation of ulcers.
In cases where there is systemic involvement, treating the underlying disease will help relieve the condition.
What Is the Prognosis of Pyoderma Gangrenosum?
The prognosis of this disease can not be predicted. In some cases, the lesions arrest, and wound healing initiates spontaneously, while in some cases, an immunosuppressive agent such as Prednisone or cyclosporine may be necessary. Avoiding trauma or injury is the best preventive strategy.
Conclusion :
Pyoderma gangrenosum is a rare skin condition characterized by ulceration of the skin. It is considered to be an autoimmune disorder, and minor injuries may result in ulceration. In addition, it may be associated with another systemic disease. Immunosuppressive agents are used to treat the condition, and care should be taken to prevent any further lesions from forming.
