Compliance problems in the dietary management of eczema

Dietary exclusions for established atopic eczema

BACKGROUND

Atopic eczema (AE) is a non-infective chronic inflammatory skin disease characterised by an itchy red rash.

OBJECTIVES

To assess the effects of dietary exclusions for the treatment of established atopic eczema.

SEARCH STRATEGY

We searched The Cochrane Skin Group Specialised Register (to March 2006), The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 1, 2006), MEDLINE (2003 to March 2006), EMBASE (2003 to March 2006), LILACS (to March 2006), PsycINFO (1806 to March 2006), AMED (1985 to March 2006), ISI Web of Science (March 2006), www.controlled-trials.com, www.clinicaltrials.gov and www.nottingham.ac.uk/ongoingskintrials (March 2006). Pharmaceutical companies were contacted where appropriate for reviews or unpublished trials.

SELECTION CRITERIA

People who have atopic eczema as diagnosed by a doctor.

DATA COLLECTION AND ANALYSIS

Two independent authors carried out study selection and assessment of methodological quality.

MAIN RESULTS

We found 9 RCTs involving a total of 421 participants of which 6 were studies of egg and milk exclusion (N=288), 1 was a study of few foods (N=85) and 2 were studies of an elemental diet (N=48). There appears to be no benefit of an egg and milk free diet in unselected participants with atopic eczema. There is also no evidence of benefit in the use of an elemental or few-foods diet in unselected cases of atopic eczema. There may be some benefit in using an egg-free diet in infants with suspected egg allergy who have positive specific IgE to eggs - one study found 51% of the children had a significant improvement in body surface area with the exclusion diet compared to normal diet (RR 1.51, 95% CI 1.07 to 2.11) and change in surface area and severity score was significantly improved in the exclusion diet compared to the normal diet at the end of 6 weeks (MD 5.50,95% CI 0.19 to 10.81) and end of treatment (MD 6.10, 95% CI 0.06 to12.14). Methodological difficulties have made it difficult to interpret these studies. Poor concealment of randomisation allocation, lack of blinding and high dropout rates without an intention-to-treat analysis indicates that these studies should be interpreted with great caution.

AUTHORS' CONCLUSIONS

There may be some benefit in using an egg-free diet in infants with suspected egg allergy who have positive specific IgE to eggs. Little evidence supports the use of various exclusion diets in unselected people with atopic eczema, but that may be because they were not allergic to those substances in the first place. Lack of any benefit may also be because the studies were too small and poorly reported. Future studies should be appropriately powered focusing on participants with a proven food allergy. In addition a distinction should be made between young children whose food allergies improve with time and older children/adults.

Determination of no-observed-adverse-effect levels and eliciting doses in a representative group of peanut-sensitized children

BACKGROUND

Current labeling practices for allergenic foods like peanut can be inadequate. For future regulatory and industry guidelines, information on no-observed-adverse-effect levels (NOAELs) and eliciting doses (EDs) for allergenic foods is necessary.

OBJECTIVE

To determine NOAEL and ED in a representative group of peanut-sensitized children, relate these data to history and sensitization, and evaluate the outcome of dietary management.

METHODS

From an overall eligible group of 96 peanut-sensitized children, a representative group of 27 was evaluated by questionnaires, skin prick test, determination of specific IgE, and double-blind placebo-controlled food challenge (DBPCFC) with peanut according to the international consensus protocol, with 9 doses ranging from 10 microg to 3 g peanut flour. Dietary management was evaluated over a 12-month period.

RESULTS

Twenty-two children (81%) had a positive DBPCFC. The NOAEL in this group was 1 mg peanut flour, corresponding to 2 mg whole peanut. The ED for subjective symptoms (10 mg to 3 g) was significantly lower than for objective symptoms (100 mg to 3 g; P = .002). Severe reactions occurred only at high doses. EDs were not correlated to previous reactions by history, skin prick test, or specific IgE levels. All patients with a positive DBPCFC were advised to follow a strict diet. During the follow-up period, 10 patients had a less strict diet likely containing traces of peanut. In 3 cases, a mild reaction occurred with food products labeled "may contain peanut."

CONCLUSION

The NOAEL in a representative group of children with peanut allergy was 2 mg. Dietary compliance in half of this group was inadequate.

Randomised controlled trial of advice on an egg exclusion diet in young children with atopic eczema and sensitivity to eggs

BACKGROUND

The role of exclusion diets in the management of atopic eczema in young children is uncertain. This randomised controlled trial evaluates the effect of excluding egg from the diet in young children with atopic eczema and sensitivity to eggs. Fifty-five such children were randomised either to a 4-week regimen, in which mothers were given general advice on care of eczema and additional specific advice from a dietician about an egg exclusion diet (diet group), or to a control group in which general advice only was given. Both groups continued conventional topical treatment. Disease activity was assessed by estimates of the surface area affected by eczema and by an arbitrary severity score. Possible egg sensitivity was identified by RAST before randomisation and after the trial by double-blind placebo-controlled egg challenge.

RESULTS

The mean reduction in surface area affected by eczema was significantly greater (p = 0.02) in the group receiving dietary advice (from 19.6% to 10.9% area affected) than in the control group (from 21.9% to 18.9%). A significant improvement also occurred in severity score (p = 0.04): from 33.9 to 24.0 units for the diet group compared with a decrease from 36.7 to 33.5 in the control group. The study suggests that advice on the dietary exclusion of eggs is useful as part of the overall management of young children with atopic eczema and sensitivity to eggs.

Controlled trial of a few foods diet in severe atopic dermatitis

Eighty five children (median age 2.3 years, range 0.3 to 13.3 years) with refractory atopic dermatitis affecting more than 12% of the body surface area, were randomly allocated to receive a few foods diet (eliminating all but five to eight foods) supplemented with either a whey hydrolysate (n = 27) or a casein hydrolysate formula (n = 32), or to remain on their usual diet and act as controls (n = 26), for a six week period. Thirty five patients who received the diet and four controls had to be withdrawn because of non-compliance with the diet or intercurrent illness. The change in dermatitis severity was evaluated by a blinded observer who estimated the extent and severity of the dermatitis, using a skin severity score. After six weeks, there was a significant reduction in all three groups in the percentage of surface area involved (controls, median reduction (MR) = 4.9% (95% confidence interval 1.5%, 11.9%); whey hydrolysate group, MR = 17.8% (8.3%, 23.0%); casein hydrolysate group, MR = 5% (1.6%, 21.2%), and skin severity score (controls, MR = 15.9 (5.0, 22.5); whey hydrolysate group, MR = 21.8 (12.8, 30.2); casein hydrolysate group, MR = 13.5 (3.4, 38.0). Sixteen (73%) of the 22 controls and 15 (58%) of the 24 who received the diet showed a greater than 20% improvement in the skin severity score. This study failed to show benefit from a few foods diet.

Few food diets in the treatment of atopic eczema

Sixty six children with severe atopic eczema were treated with highly restricted ('few food') diets followed, if they improved, by serial reintroduction of excluded foods. Twenty four patients (36%) improved considerably during the few food phase of the diet. Fifteen of these (23% of the study group) maintained this improvement on dietary treatment, of whom three abandoned the diet after periods ranging from six to 10 months, despite continued benefit, because they found the dietary restrictions too arduous. Thus 12 out of 66 children (18%) with severe eczema experienced prolonged and useful benefit from this dietary manoeuvre. Double blind food challenges performed in 10 patients failed to establish that parental identification of provoking foods is reliable. A search for historical and in vitro predictors of diet responsiveness was unsuccessful in this series.

Dietary manipulation in childhood atopic dermatitis

The dietary habits of 73 children seen consecutively in a dermatology out-patient department were studied to ascertain the nature and frequency of dietary manipulation and to assess any potential hazards. Although most children had only mild flexural dermatitis, 71% had had significant alterations made to their diet before attendance at hospital. Almost all diets were unsupervised and only six children had seen a dietitian. Over half had been started on diets before any professional advice had been sought. Information on diet had come from media, books or magazines (51%), friends (32%), general practitioners (27%) and district nurses or health visitors (18%). The major dietary alterations included the exclusion of eggs, dairy products and food additives, and the use of soya and goat's milk. Under 10% of patients claimed benefit from these largely unsupervised diets. Harmful practices included the frequent use of unboiled, unpasteurized goat's milk, unmodified goat's milk in a baby of 4 months and the use of severely restricted diets. Three children (6%) in the diet group had been on diets which were considered by a hospital dietitian to be particularly dangerous. However, there was no evidence of growth retardation, failure to thrive or specific deficiency syndromes in the group we studied. Uncontrolled, unsupervised and often prolonged dietary alterations are commonplace in children with atopic dermatitis. This is a potentially serious health problem.

Role of diet in treating atopic eczema: elimination diets can be beneficial

Images

Food intolerance: our practice

This paper describes the clinical presentation of food allergy and/or intolerance (F.A.I.). The role of a diagnostic dietary trial is reviewed. Finally dietary management is discussed.

Artificial food additive intolerance in patients with angio-oedema and urticaria

43 children who presented with angio-oedema and/or urticaria and who responded to an additive-free diet were challenged with artificial food additives in a double-blind study. 24 children reacted to 1 or more of the additives. 18 children did not react to any additives and remained well when a normal diet was re-introduced. Aspirin sensitivity was found in only 1 of the 24 children who could not tolerate additives. Atopy was less common in these patients than in the general population. The mechanism of additive intolerance is unknown and double-blind challenge is the only reliable means of diagnosis.

Diet and atopic dermatitis

Prevention or modification of the onset of atopic dermatitis has been difficult to document through prolonged breast feeding or delayed introduction of solid foods. Dietary management of established atopic dermatitis is not routinely indicated for the majority of patients. Dietary management of atopic dermatitis should not be continued indefinitely. Gradual reintroduction of the offending food(s) is often appropriate. The foods most commonly avoided in the management of atopic dermatitis are cow's milk, wheat, eggs, and nuts. Severe or prolonged dietary restrictions should not be instituted without full consideration of their impact on the patient's general health.

Food hypersensitivity and atopic dermatitis: evaluation of 113 patients

One hundred thirteen patients with severe atopic dermatitis were evaluated for food hypersensitivity with double-blind placebo-controlled oral food challenges. Sixty-three (56%) children experienced 101 positive food challenges; skin symptoms developed in 85 (84%) challenges, gastrointestinal symptoms in 53 (52%), and respiratory symptoms in 32 (32%). Egg, peanut, and milk accounted for 72% of the hypersensitivity reactions induced. History and laboratory data were of marginal value in predicting which patients were likely to have food allergy. When patients were given appropriate restrictive diets based on oral food challenge results, approximately 40% of the 40 patients re-evaluated lost their hypersensitivity after 1 or 2 years, and most showed significant improvement in their clinical course compared with patients in whom no food allergy was documented. These studies demonstrate that food hypersensitivity plays a pathogenic role in some children with atopic dermatitis and that appropriate diagnosis and exclusionary diets can lead to significant improvement in their skin symptoms.

Allergic form of Meadow's syndrome (Munchausen by proxy)

We present 17 children from 11 families with the allergic form of Meadow's syndrome. In all cases their mothers believed that they had severe disease due to allergies--in 16 cases to foods and in one to house dust mite. The maternal obsession with allergen avoidance resulted in bizarre diets and life styles. Most mothers were articulate and middle class, and many had marital problems (three single parents). They had a limpet-like attachment to their child and insisted on many medical consultations. Management proved very difficult and despite careful exclusion of allergic disease, many remained on diets and failed allergy clinic follow up. In most cases the obsession with allergy had been initiated by doctors.