Erythema ab igne and Crohn’s disease
- Dr Mark P Tighe, Paediatric Specialist Registrar, Child Health, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK;
- Accepted 17 January 2008
This 13-year-old boy presented with a 2-month history of abdominal pain, bloody diarrhoea and weight loss (10 kg). On examination, he was wasted and had a non-tender, reticular, macular, pigmented rash on his anterior abdominal wall (fig 1). He attributed the rash to frequent use of a hot water bottle, which had helped to settle his pain. Inflammatory markers were raised, and abdominal ultrasound showed bowel-wall thickening. Endoscopy and biopsy confirmed Crohn’s disease, and he has responded well to treatment with exclusive enteral nutrition.
The skin rash is typical of erythema ab igne. Erythema ab igne is a reticular erythematous hyperpigmentation caused by repeated skin exposure to moderate heat. Initial transient reticular erythema progresses to pigmentation.1 It is usually asymptomatic, although local irritation can occur. Mildly hyperpigmented lesions resolve within months if the heat source is removed. A 3–4 mm punch biopsy is recommended if there is doubt about the diagnosis or malignant change is suspected.1
In the 19th century, erythema ab igne was seen on the legs of those who sat close to open fires and those in certain occupations (eg, cooks and chimney sweeps). There are recent reports of causation by a car heater and laptop.2 3 There is only one report of it in a child (with atopic eczema).4 It has been seen in adults with abdominal malignancy.5
This is the first report of erythema ab igne in a child with inflammatory bowel disease. The probable cause of the rash is prolonged skin contact with a hot water bottle to ease pain, in the context of a child with significant gut pathology and wasting.
Competing interests: None declared.
Ethics approval: Patient and parental consent has been given for the publication of this photo.
Patient consent: Informed consent was obtained for publication of fig 1.