Can Low Histamine Diet Reduce Symptoms of Patients With Idiopathic Urticaria?
Trial Snapshot
- Phase
- Not Applicable
- Status
- Terminated
- Sponsor
- Enrollment
- 8
- Locations
- 1
- Primary Endpoint
- The change in Mean Total Symptoms Score (MTSS) from baseline between groups
Study Overview
Brief Summary
Histamine is a biologically active component that can be found in many foods and beverages. Intake of excessive histamine from foods or beverages, can trigger symptoms including urticaria. A low histamine diet has been recommended as one of the possible treatments for patients with chronic urticaria. There are very few studies to confirm the effectiveness of such diets and, to the investigators' knowledge, none from Asia where high histamine containing meals are often eaten (personal observations). The objective of the present study is to investigate the therapeutic effect of low histamine diet in relieving symptoms in patients with chronic urticaria with or without angioedema, and / or pruritus (U/A/P). The investigators hypothesize that following a low histamine diet for 4 weeks, the symptoms of patients with chronic U/A/P should improve.
Detailed Description
A double blinded parallel randomized control study over 4 weeks will be conducted to assess the effectiveness of a histamine-restricted diet. Neither the subjects nor the medical investigator will know which diet is being prescribed.
The study will only be conducted after ethical approval has been granted and with informed consent. If it is a child, informed consent will be obtained from a parent. Subject has to pay his/her consultation fee for doctor's and dietitian's consultation and skin prick and/or blood tests at the first visit as normal but there will be no charge for subsequent visits in relation to the trial.
A period of 4 weeks on the low histamine diet has previously been shown to be sufficient to determine whether dietary manipulation will help in the management of the urticaria symptoms.
Selection Criteria and sample size calculation 78 subjects who come to Allergy Centre for treatment of idiopathic urticaria, with or without angioedema and pruritus (U/A/P), will be randomized into two parallel groups; treatment group (TG) will be asked to follow a histamine-restricted diet for 4 weeks and the control group (CG) will be asked to follow a well-balanced diet instructed by a dietitian for 4 weeks. A well-balanced diet for the CG subject is tailor-made by the dietitian according to subject's usual intake to ensure that the subject's energy requirement is met and all food groups are consumed. Subjects in both groups are also instructed to have adequate water intake during the study period. Both groups are asked to record food diary and symptoms during the study period. Consent form will state that it is a study to compare the efficacy of both diets. After the study period, subjects in the CG will be able to follow a low histamine diet if this is proven to be beneficial, so everyone will have the potential to benefit from the low histamine diet and vice versa for the TG subjects.
Low Histamine Diet Histamine is present in almost all foods in small quantities. Its presence increases with maturation of the food. High quantities of histamine are found mainly in products of microbial fermentation, such as aged cheese, sauerkraut, wine, and processed meat. Some oriental foods with high histamine content are also included.The current Low Histamine Diet sheet of Hong Kong Sanatorium & Hospital will be used (Appendix I).
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Double (Participant, Outcomes Assessor)
Eligibility Criteria
- Ages
- 8 Years to — (Child, Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Urticaria +/- angioedema present for a minimum of 6 weeks;
- •Agree to be on anti-histamine prn;
- •Age older than 8 years old, with no upper age limit;
- •Causes such as parasite infestation, microbial and viral infections, autoimmune disease, or other pathology that could account for the U/A/P should be excluded;
- •Skin prick test and/or radioallergosorbent (RAST) test are negative for all food allergens tested, or patient had achieved no symptomatic improvement after strict avoidance of all skin test-positive foods;
Exclusion Criteria
- •Pregnant or breast feeding women;
- •Patients who is taking central nervous system (CNS) acting agents (including tranquilizers, antidepressants, sedatives, hypnotics or antiepileptics) at any time;
Arms & Interventions
Well-balanced diet
Diet tailor-made by the dietitian according to subject's usual intake to ensure that the subject's energy requirement is met and all food groups are consumed.
Intervention: Well-balanced diet (Other)
Treatment group (on low histamine diet)
78 subjects who come to Allergy Centre for treatment of idiopathic urticaria, with or without angioedema and pruritus (U/A/P), will be randomized into two parallel groups; treatment group (TG) will be asked to follow a histamine-restricted diet for 4 weeks and the control group (CG) will be asked to follow a well-balanced diet instructed by a dietitian for 4 weeks. A well-balanced diet for the CG subject is tailor-made by the dietitian according to subject's usual intake to ensure that the subject's energy requirement is met and all food groups are consumed.
Intervention: Treatment group (on low histamine diet) (Other)
Outcomes
Primary Outcomes
The change in Mean Total Symptoms Score (MTSS) from baseline between groups
Time Frame: 4 weeks
When a subject comes for the first consultation (randomization week), he/she will be given a 4-point scale questionnaire (see Appendix II) to evaluate his/her own symptoms (pruritus severity and number of wheals). This will be completed once every evening for a week prior to the 4-week treatment period. The pruritus severity score and the number of wheals during this run in week will be averaged and used as the mean baseline score. The summation of mean pruritus score (MPS) and the mean number of wheals (MNW) will be the mean total symptoms score (MTSS) for the baseline period. Then comparison between the change in Mean Total Symptoms Score (MTSS) from baseline between treatment group and control group.
Secondary Outcomes
- the change in mean number of wheals (MNW) between groups(4 week)
- the comparison of area under the curve (AUC for the trend) for MTSS, MPS, MNW, GSS and DCS between the groups during the 4-week period(4 week)
- the change in mean pruritus score (MPS) between treatment group and control group(4 week)
- the change in global symptoms severity (GSS) by medical investigator between groups(5 weeks)