[Allergic colitis: clinical and morphological aspects in infants with rectal bleeding]

Food protein-induced allergic proctocolitis in infants: Literature review and proposal of a management protocol

Food protein-induced allergic proctocolitis (FPIAP) is a condition characterized by inflammatory changes in the distal colon in response to one or more foreign food proteins because of immune-mediated reactions.

FPIAP prevalence estimates range widely from 0.16% in healthy children and 64% in patients with blood in stools.

In clinical practice, FPIAP is diagnosed when patients respond positively to the elimination of a suspected triggering food allergen. Nevertheless, significant proportions of infants get misdiagnosed with IgE mediated allergy and undergo unnecessary dietary changes.

Diagnosis is based on clinical symptoms, a good response to an allergen-free diet and the recurrence of symptoms during the “allergy challenge test”. Sometimes clinical features may be non-specific and the etiology of rectal bleeding in childhood may be heterogeneous. Therefore, it is crucial to exclude a variety of other possible causes of rectal bleeding in the pediatric age group, including infection, anal fissure, intestinal intussusception and, in infants, necrotizing enterocolitis and very early onset inflammatory bowel disease. The diagnostic workup includes in those cases invasive procedures such as sigmoidoscopy and colonoscopy with biopsies.

The high prevalence of FPIAP contrasts with the lack of known information about the pathogenesis of this condition. For this reason and due to the absence of a review of the evidence, a literature review appears necessary to clarify some aspects of allergic colitis.

The aim of the review is to fill this gap and to lay the foundations for a subsequent evidence-based approach to the condition.

Allergic enteritis in children

The gastrointestinal form of food allergy is very common in children. The most frequently observed types are allergic proctitis and proctocolitis. In most cases the symptoms subside within the first 2 months of life. The babies seem healthy, and the only abnormality is a small amount of blood in stool. Symptoms can also include small intestine inflammation and colitis. Patients may present with irritability, abdominal pain, flatulence, colic, postprandial vomiting, chronic diarrhoea, and hindered physical development. The diagnosis of allergic enteritis is based on the clinical examination and the results of additional tests including an endoscopy of the lower digestive tract with histopathological assessment. Cow’s milk proteins are the most common nutrition proteins responsible for the development of the symptoms of allergic enteritis. The most essential method of treating allergic enteritis is the elimination diet. The symptoms should subside within 1–2 weeks from the beginning of the diet.

Allergic proctocolitis: the clinical evolution of a transitory disease with a familial trend. Case reports

Allergic colitis is a clinical manifestation of food allergy during the first months of life. It is estimated that genetic factors play a role in the expression of this allergic disease. This case report described the clinical progress of infants who were cousins from two distinct family groups with allergic colitis. Five infants under six months of age and of both sexes were studied, with a diagnosis of allergic colitis characterized clinically and histologically by (1) rectal bleeding; (2) exclusion of infectious causes of colitis; (3) disappearance of symptoms after elimination of cow's milk and dairy products from the child's and/or the mother's diet. Patients were submitted to the following diagnostic investigation: complete blood count; stool culture; parasitologic examination of stools; rectoscopy or colonoscopy; and rectal biopsy. Patient age varied from 40 days to six months; three were males. All patients presented with complaints of intense colic and rectal bleeding. The colonoscopy showed presence of hyperemia of the mucosa with microerosions and spontaneous bleeding upon the procedure. Microscopy revealed the existence of colitis with eosinophilia >20 e/HPF. Patients were treated with a hypoallergenic formula and showed remission of symptoms. After one year of age, all were submitted to an oral challenge with a milk formula and presented food tolerance. Allergic colitis is a disease with evident genetic inheritance and a temporary character.

Eosinophilic colitis in infants

OBJECTIVE

To review the literature for clinical data on infants with allergic or eosinophilic colitis.

DATA SOURCE

MEDLINE search of all indexes was performed using the words "colitis or proctocolitis and eosinophilic" or "colitis or proctocolitis and allergic" between 1966 and February of 2013. All articles that described patients' characteristics were selected.

DATA SYNTHESIS

A total of 770 articles were identified, of which 32 met the inclusion criteria. The 32 articles included a total of 314 infants. According to the available information, 61.6% of infants were male and 78.6% were younger than 6 months. Of the 314 patients, 49.0% were fed exclusively breast milk, 44.2% received cow's milk protein, and 6.8% received soy protein. Diarrheal stools were described in 28.3% of patients. Eosinophilia was found in 43.8% (115/263) of infants. Colonic or rectal biopsy showed infiltration by eosinophils (between 5 and 25 per high-power field) in 89.3% (236/264) of patients. Most patients showed improvement with the removal of the protein in cow's milk from their diet or the mother's diet. Allergy challenge tests with cow's milk protein were cited by 12 of the 32 articles (66 patients).

CONCLUSIONS

Eosinophilic colitis occurs predominantly in the first six months of life and in males. Allergy to cow's milk was considered the main cause of eosinophilic colitis. Exclusion of cow's milk from the diet of the lactating mother or from the infant's diet is generally an effective therapeutic measure.