Cutaneous manifestations of inflammatory bowel disease

What is inflammatory bowel disease?

There are two main forms of inflammatory bowel disease (IBD) — ulcerative colitis and Crohn disease. Both are characterised by abdominal pain and diarrhoea, sometimes with bleeding.

• Ulcerative colitis typically involves only the colon (large bowel).
• Crohn disease can affect any part of the gastrointestinal tract from the lips to the anus with scattered lesions. Crohn disease is characterised on pathology by non-caseating granulomas but these are not always found on bowel biopsy.

Although the two diseases are quite separate, accurate diagnosis can sometimes be difficult especially in the early stages. Therefore the involvement of other organs can help to make the distinction.

Skin disease and inflammatory bowel disease

DermNet NZ includes the following pages about inflammatory bowel disease:

• Oral manifestations of inflammatory bowel disease
• Crohn skin disease
• Genital Crohn disease
• Orofacial Crohn disease
• Orofacial granulomatosis
• Pyodermatitis-pyostomatitis vegetans

Other disorders associated with inflammatory bowel disease

Some nonspecific conditions occur more commonly with IBD than in the general population, but also do occur without bowel disease, and the pathology is not diagnostic for the bowel disease.

These include:

• Aphthous ulceration
• Angular cheilitis
• Neutrophilic dermatoses: acute febrile neutrophilic dermatosis (Sweet syndrome), pyoderma gangrenosum and bowel bypass syndrome (bowel-associated dermatitis-arthritis syndrome)
• Erythema nodosum
• Stoma skin problems
• Anal cancer.

IBD can lead to complications of malabsorption caused by bowel inflammation or surgery, resulting in deficiencies in vitamins and minerals.

• Malnutrition
• Iron deficiency
• Pellagra (vitamin B3, niacin deficiency)
• Scurvy (vitamin C deficiency)
• An acrodermatitis enteropathica-like condition (zinc deficiency)
• Vitamin A deficiency
• Vitamin B12 deficiency (in Crohn disease, as B12 absorbed from small bowel)
• Folic acid deficiency
• Vitamin K deficiency — bleeding

Skin reactions may also arise to medications prescribed for IBD.