**4.3.4 Types of OFC**

There are various types of OFC that may be clinically indicated, including open, singleblind, double-blind, and placebo-controlled trials. The choice of the type of OFC is based on a clinical assessment of the potential for bias in the interpretation of the results) [32]. Open OFC is the unmasked, unblinded administration of a food in its natural form. Open OFC is recommended for IFA because IFA is associated with a clear clinical manifestation. Moreover, in NFA, open OFC is effective in the clinical setting and can be performed on an out-patient basis. Open OFC is a cost-efficient procedure that saves substantial time and resources. It is thus considered to be a reasonable first choice for evaluating an adverse reaction to a food when the need for an OFC has been established.

Blinding and masking by mixing the challenge food with a masking vehicle or placing the food in vehicles, including opaque capsules or powders, reduces bias [32]. In the singleblind OFC, the observer but not the patient knows the food being tested. In the double-blind

More than 50% of AD patients have NFA . Without the control of allergy provocation, AD cannot be effectively controlled [21]. As a first step in the diagnosis of food allergy, dietary restrictions should be initiated. If a patient shows improvement on an elimination diet, a food allergy to the restricted foods should be strongly suspected. An optimal elimination diet can be achieved by providing a list of the foods to be restricted, which in turn can be

In the case of breast-fed infants, maternal elimination diets are recommended. Once a maternal elimination diet is implemented, improvements are often observed in the infant [31]. If eczema improves during the elimination diet, the clinical relevance of the eliminated foods should be

Through OFC, the suspected foods should be listed with the classification of type of allergy, and a relevant elimination diet that eliminates only suspected foods should result in an improvement of AD symptoms [2]. The order for the OFC should prioritise NFA before IFA. Additionally, the importance of certain foods should be considered according to the patient's wishes. An OFC for NFA should generally precede an OFC for IFA. Each OFC is

1. Principle of oral food challenge in AD (Goldmann's triad): intake, elimination diet and

The diagnosis of food allergy follows the standard principle of Goldmann's triad [19]. When patients show symptoms and signs after the ingestion of suspected causative foods, an elimination diet is initiated. If the patient shows improvement with this diet, the eliminated food is strongly suspected as the cause of AD. If the patient again shows the clinical manifestation with subsequent food challenge, the challenged food is confirmed as

An elimination diet is the first effective way to confirm a food allergy in AD. However, a proper elimination diet is necessary [2]. Unless such a diet is performed, it is likely that elimination will be ineffective. A proper elimination diet is essential and should not be

There are various types of OFC that may be clinically indicated, including open, singleblind, double-blind, and placebo-controlled trials. The choice of the type of OFC is based on a clinical assessment of the potential for bias in the interpretation of the results) [32]. Open OFC is the unmasked, unblinded administration of a food in its natural form. Open OFC is recommended for IFA because IFA is associated with a clear clinical manifestation. Moreover, in NFA, open OFC is effective in the clinical setting and can be performed on an out-patient basis. Open OFC is a cost-efficient procedure that saves substantial time and resources. It is thus considered to be a reasonable first choice for evaluating an adverse

Blinding and masking by mixing the challenge food with a masking vehicle or placing the food in vehicles, including opaque capsules or powders, reduces bias [32]. In the singleblind OFC, the observer but not the patient knows the food being tested. In the double-blind

confirmed with standardised, physician-supervised oral food challenges to the mother.

determined by clinical statistics.

2. Breast-fed infants

**4.3.3 Oral food challenge** 

challenge test

the cause of AD.

**4.3.4 Types of OFC** 

omitted.

conducted according to the relevant protocols.

2. Proper elimination of foods as an absolute condition for OFC

reaction to a food when the need for an OFC has been established.

OFC, the challenge material is provided by a third party, such as a dietitian, and the patient, the patient's family, and the observer are unaware of when the test food is administered. Bias is thus minimised. Placebo-controlled challenges may be administered in either a single-blind or double-blind fashion.
