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Therapeutic Strategies

Pyoderma Gangrenosum

Timothy Berger Bruce Wintroub

Saturday, January 01, 2011

Overview

Pyoderma gangrenosum (PG) is a neutrophilic dermatosis defined by its characteristic morphology. It is a diagnosis of exclusion, and can be simulated by various vascular and infectious conditions.Treatment is determined by the extent and rapidity of the cutaneous process. Treatment with granulocyte-monocyte colony stimulating factor (GM-CSF) may cause PG-like lesions. In these cases, lesions may respond by stopping the GM-CSF and with topical treatment.

First Steps

  1. Systemic corticosteroids are the initial treatment of choice for patients with established ulcerations and with multiple lesions. Initial therapy is 1 mg/kg or higher per day. After a response is seen, gradually taper the dose. If no response is seen in a week, a second agent should be added.
  2. Local therapy is very effective for early, superficial, and those which are not rapidly progressive. Consider these options:
    1. Tacrolimus ointment 0.1-0.3% (compounded) applied into the ulcer bed twice daily, covered with a Telfa dressing. Tacrolimus ointment mixed with Orabase may be used for peristomal PG associated with inflammatory bowel disease.
    2. Intralesional triamcinolone acetonide 10 mg/mL to the edge of the lesion.
  3. PG lesions are easily inflamed; debridement should generally be avoided, as it will lead to exacerbation of the lesion.

Subsequent Steps

  1. In superficial lesions and those with limited progression, consider the following:
    1. Thalidomide 100-400 mg daily for 2-4 weeks, then tapered if the patient responds.
    2. Dapsone 100-200 mg daily, monitoring for anemia.
    3. Colchicine 0.6-1.2 mg twice daily, to tolerance (diarrhea limits dosing) may be added to the dapsone for additional effect.
    4. Clofazamine 100 mg twice daily.
  2. If the response to systemic steroids is inadequate and the process is extremely rapid, in addition to systemic steroids, treat with cyclosporine A at an initial dose of 5-10 mg/kg/day. Response should be dramatic and will permit rapid reduction of systemic steroids (as long as cyclosporine complications are not encountered). For patients in whom cyclosporine fails or is not tolerated, oral tacrolimus may be used instead.
  3. In refractory cases, the following agents can be used individually or added to treatment with systemic steroids and cyclosporine:
    1. Pulse systemic steroids monthly, either with intravenous methylprednisolone up to 1 g; or oral dexamethasone 100 mg daily for 5 consecutive days may be added to the cyclosporine and daily systemic steroid doses.
    2. Mycophenolate mofetil 1.0 g twice daily may be added to the combination of systemic steroids and cyclosporine, and may benefit some refractory patients.
    3. Anti-Tumor Necrosis Factor Antibodies: Infliximab 5 mg/kg intravenous infusions at weeks 0, 2 and 6 or every 3 weeks in a series until improvement is noted. Etanercept 50 mg twice weekly may also be effective. TNF blockers have become rescue therapy for PG and have greatly improved the prognosis of this condition.
    4. Azathioprine 100-300 mg daily can be an effective steroid-sparing agent. Cyclosporine, mycophenolate, and TNF inhibitors are associated with more rapid response, relegating azathioprine to use as a steroid-sparing agent for long-term management when required.
    5. Pulse cyclophosphamide, once used in refractory cases, is now used only in the rare PG case in which the above agents are ineffective.

Ancillary Steps

  1. Vapor-permeable, hydrophilic membranes help control pain and may hasten reepithelialization. Dressings can remain in place for 3-7 days. Removal must be very gentle to avoid pathergy (appearance of disease in sites of trauma).
  2. Although skin grafts often will "take" in patients receiving appropriate immunosuppressive therapy as outlined above, pathergy at the donor site may occur. Human skin equivalents or cultured keratinocytes may be used to avoid this potential complication. They are very effective in reducing the pain associated with PG, and may shorten the course of immunosuppressive treatment required to heal the ulceration.
  3. Hyperbaric oxygen reportedly accelerates healing rates in some patients.
  4. Workup for an associated disease is mandatory, since control of PG often can be achieved with therapy of the underlying disease process. Inflammatory bowel disease [i.e., both ulcerative colitis and regional enteritis (Crohn's)] is the most common associated illness.
  5. Healed lesions of PG are extremely susceptible to trauma, which can reactivate previously quiescent lesions. Emollients should be employed routinely, and both elevation and support stockings should be prescribed to minimize venous pooling that can lead to leg ulcers.

Pitfalls

  1. PG-like lesions occur in a host of other diseases, including carcinomas, mycobacterial and other infections, halogenoderma, gummatous syphilis, Wegener's granulomatosis, polyarteritis nodosa, antiphospholipid antibody syndrome, cholesterol emboli, and factitia. At the institution of therapy, strong consideration should be given to performing an incisional biopsy for routine histology and cultures, and performing appropriate laboratory tests to exclude the above conditions.
  2. Pathergy occurs in many patients with PG, thus all but the most gentle debridement or other manipulations should be avoided.
  3. Iodides can aggravate lesions of PG.
  4. Dapsone can cause a host of toxic and idiosyncratic side effects. Accelerated hemolysis owing to shortened red cell lifespan occurs in all patients, but can be life-threatening in patients with glucose-6-phosphate (G6PD) deficiency.
  5. Immunosuppressive therapy and anti-TNF treatment may be complicated by serious infections. Baseline purified protein derivative (PPD) and prophylaxis for pneumocystis pneumonia should be considered when appropriate.
  6. Thalidomide is a potent teratogen, therefore all female patients treated with this agent must be entered in a standardized pregnancy prevention program.

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