A 38-year-old woman presented with a painful and persistent lesion on her right leg. She thought it might have been an infected insect bite although it was not itchy. She had been feeling tired over the past months, had lost weight and had been having abdominal pains.
The patient appeared slim and pale. Examination of the lesion revealed a blue tinged ulcer with necrotic overhanging edges. Her abdomen was generally tender and she had anal fissures.
What is the diagnosis, differential diagnosis and management?
Diagnosis and management
This patient has pyoderma gangrenosum secondary to Crohn's disease. It is a non-infective, non-gangrenous lesion that may be very painful. Other diseases associated with pyoderma include ulcerative colitis, leukaemia, inflammatory arthritides, Wegner's granulomatosis, AIDS and autoimmune hepatitis.
Along with routine blood tests, investigations should be tailored to these diseases as well as excluding the differential diagnoses. Management involves treating any underlying condition, topical treatments or systemic steroids and steroid sparing immuno-suppressants. Strong analgesia may be required.
Possible different diagnosis
- Squamous cell carcinoma.
- Behcet's disease.
- Vascular insufficiency.
Squamous cell carcinoma
- Usually on sun-exposed areas such as the legs and arms.
- Raised border, crusted surface. Tends to ulcerate.
- Excision and biopsy confirms diagnosis.
- Sun protection is essential.
Contributed by Dr Raj Thakkar, a GP in Wooburn Green, Buckinghamshire