Clinical Challenge: Painful erosions on the bilateral inguinal folds and intergluteal cleft

Crohn's disease is characterized by chronic granulomatous inflammation of the intestinal tract. The disorder is thought to be the result of an excessive T-cell response triggered by disruption in the gut flora and defective bacterial clearance.1 Common symptoms are diarrhea,...

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Crohn’s disease is characterized by chronic granulomatous inflammation of the intestinal tract. The disorder is thought to be the result of an excessive T-cell response triggered by disruption in the gut flora and defective bacterial clearance.¹ Common symptoms are diarrhea, constipation and pain. 

Numerous organ systems may be involved, and patient complaints are varied.  Development of lesions that are not contiguous with the gastrointestinal tract is sometimes referred to as metastatic Crohn’s disease.

Skin involvement occurs in approximately 25% to 40% of patients, and manifestations include: pyoderma gangrenosum, erythema multiforme, erythema nodosum, leukocytoclastic vasculitis and nutritional skin changes in severe cases.²  

Cutaneous Crohn’s disease with development of non-caseating granulomas in the skin is quite rare, with fewer than 100 cases reported in the literature.¹ Genital skin is involved in about one-half of cases of cutaneous Crohn’s disease and initially presents with labial or scrotal erythema and edema.²

Perianal lesions are frequently observed and may consist of ulcers, fissures, sinus tracts, abscesses or vegetating plaques.³ These lesions can be extremely painful and debilitating.

Diagnosis

Unfortunately, there is no definitive test to evaluate for cutaneous Crohn’s, but bowel involvement is required to make the diagnosis. Despite this criterion, in 20% of reported cases, cutaneous lesions preceded bowel involvement by as many as 8 years.¹  Furthermore, the severity of cutaneous lesions does not correlate with the degree of intestinal disease. In cases with minimal bowel symptoms, the diagnosis can be very difficult. 

A skin biopsy is a helpful diagnostic tool, but may not be able to differentiate cutaneous Crohn’s disease from other granulomatous skin disorders, such as sarcoidosis, lupus vulgaris or foreign body granulomas. Additionally, since only a small portion of the lesion is biopsied, the characteristic features can easily be missed due to sampling error. 

The histopathologic appearance of cutaneous Crohn’s consists of superficial and deep dermal nodular, non-caseating epitheliod tubercles with surrounding lymphocytes.¹  Special stains for deep fungal organisms and acid-fast bacilli should be performed to rule out infectious etiology.       

Treatment

Cutaneous Crohn’s disease tends to be chronic and prolonged. Therapies aimed at improving the intestinal disease often improve the skin lesions as well.

Systemic medications include sulfasalazine, systemic corticosteroids, azathioprine, 6-mercaptopurine, cyclosporine, mycophenolate mofetil, methotrexate, and TNF-α inhibitors such as infliximab (Remicade, Centocor Ortho Biotech) and adalimumab (Humera, Abbott). Oral metronidazole (Flagyl, Pfizer) 250 mg three times a day has also been found to be effective and has now become a first-line agent.¹

Cutaneous lesions can also be treated topically with high-potency corticosteroids and tacrolimus ointment (Protopic, Astellas).

Surgical correction of fistula or removal of necrotic bowel may be required, but excision of skin lesions is generally not recommended given the risk of recurrence and poor wound healing leading to wound dehiscence.

Kristy Fleming, MD, is a third year dermatology resident at Baylor College of medicine.

References:

1. Bolognia J, Jorizzo JL, Rapini RP. Dermatology 2nd Ed. Elsevier; 2008: 1433-1434.

2. James WD, Berger TG, Elston DM. Andrew’s Diseases of the Skin Clinical Dermatology. 10th ed. Pennsylvania: Saunders Elsevier; 2006: 798.