Colonoscopy to the terminal ileum showed severe patchy inflammation with inflammatory pesudopolyps, deep linear ulcerations and cobblestone appearance throughout the whole colonic mucus and the terminal ileum (fig 1).

Histopathology of the mucosal biopsy taken from the terminal ileum and different parts of the colon showed moderate increase in the lamina propria of mononuclear inflammatory cells and neutrophils indicating cryptitis and crypt abscess. No granulomata were seen.

After 2 months of treatment with conventional treatment, perianal disease was getting worse. More fistulas appeared and there was more perineal destruction (fig 2A).

Several case reports of young children with Crohn’s disease have been published.^4–8 However, reports of neonatal onset are limited.^4,5,7 They include all 12 patients reported by Miller and Larsen,⁷ one of seven patients reported by Marx et al,⁵ and two of the four cases reported by Cohen et al.⁴

The diagnosis of Crohn’s disease in this infant was made on clinical grounds confirmed by the presence of chronic histological changes in the colon and terminal ileum and endoscopic features compatible with Crohn’s disease.

The aetiology of Crohn’s disease remains unknown, but the interaction between genetic and environmental factors plays a role. Cohen et al⁴ reported infantile Crohn’s disease occurring in three siblings and their first degree cousin in an Arab Bedouin family, highlighting the importance of genetic factors, especially in early onset disease.

The differential diagnosis of infantile Crohn’s disease should include allergic colitis as the main cause of non-infectious colitis in this age group⁹; however, this patient did not respond to elemental formula, and there were no histological changes to suggest allergy.

All infants with non-infective colitis with a proposed diagnosis of Crohn’s disease need to be investigated for immunodeficiency since it can mimic the presentation of Crohn’s disease,^10,11 and could result in lethal consequences following treatment with immunosuppressive therapy. Immune abnormality was excluded in our case by finding normal immunoglobulin, serum complement, total lymphocytes and lymphocyte subset. Nitroblue tetrazolium test was also performed and excluded the possibility of chronic granulomatous disease in this infant.

In the presence of recurrent mouth ulcers and chronic diarrhoea, especially if the diarrhoea is unresponsive to oral prednisolone and sulfasalazine, with the characteristic ulcers in biopsy, Behçet’s syndrome should always be considered.¹² Absence of mouth ulcers in this patient and the presence of perianal disease make this possibility unlikely.

Perianal fistulas in infants with Crohn’s disease was reported in four infants by Cohen et al⁴ and in two infants by Marx et al.⁵ Infants can have severe perianal disease even with mild bowel involvement.⁸ Extension of the perianal disease to involve the genitalia, whether direct or metastatic through possible microfistulae, can be complicated by anal stricture, which has been reported by the author in older children with Crohn’s disease involving the genitalia.¹³

Management of perianal disease in Crohn’s patients has always been difficult. Some improvement can occasionally be achieved by the use of metronidazole and azathioprine; however, this improvement is not usually sustained. The reported outcome of surgical intervention in fistulising disease in children is variable.^4,7,8 Thus conservative treatment is usually recommended. The new biological therapy anti-TNFα has been very successful when used in fistulising disease in adults with Crohn’s disease.² But experience with this new therapy in young infants is lacking, and there is concern about the immunomodulatory aspects in a young child whose T cell repertoire is developing. This child has normal immune function 10 months following the last dose of infliximab.

It is also important to consider the infection risk of infliximab in this population, since TNFα is an important component of the immune system’s response to a variety of infections. TNFα inhibitors can cause serious infections.¹⁴ These infections have included bacterial sepsis,¹⁵ tuberculosis,¹⁶ invasive fungal¹⁷ and other opportunistic infections.^18,19 This infant had two episodes of bacterial sepsis with E coli and S aureus that were treated with appropriate antibiotics. Failure to recognise early symptoms and signs of infection can result in fatal outcome.^20,21 Parents should be educated about the recognition of signs and symptoms of infection during and after treatment with infliximab, and should have access to appropriate medical care. This risk of infection must be interpreted in the context of the potential benefits and of the possible adverse effects of conventional therapies. Repair of the fistulas and improvement of the severe skin damage appears so far to justify its use in the case presented here.