Dietary Approach to Mild-to-moderate Psoriasis

Condition(s) studied

Investigational drug(s) / intervention(s)

Open wheat challenge: Patients randomized to intervention diet group will have to follow a diet with elimination of wheat and cow's milk products for 2 months; after that they will be exposed to an open wheat challenge, with reintroduction of wheat. After 2 weeks of open diet, or whenever dermatologic, intestinal and/or extraintestinal symptoms should return or intensify, all patients will be revaluated and will end the study.

Placebo challenge: Patients randomized to control diet group will have to follow a diet with elimination of rice and turkey's meat products for 2 months; after that they will crossover to a wheat and cow's milk products free diet and, finally, after 2 months, they will be exposed to an open wheat challenge, with reintroduction of wheat. After 2 weeks of open diet, or whenever dermatologic, intestinal and/or extraintestinal symptoms should return or intensify, all patients will be revaluated and will end the study.

Study summary

Psoriasis is a systemic chronic inflammatory immune-mediated disease whose etiopathogenetic mechanisms involve genetic predisposition, and immunological and environmental factors. Its prevalence is about 3% in adults, and it is characterized by well-demarcated, erythematous plaques, covered by silvery-white scales, in elbows, knees, trunk, and scalp. However, psoriasis is far from being considered just a dermatologic condition because the cytokine's cascade, which lays behind its inflammatory and immune-mediated pathogenesis, can determine multiple systemic manifestations. In addition, several patients with psoriasis often complains of gastrointestinal (GI) symptoms. Therefore, authors focused their attention over the gut-skin axis and its possible pathogenetic and immunoregulatory role in psoriasis (i.e., altered gut barrier, increased blood concentration of gut microbiota-derived metabolites, systemic inflammation). In this context, several dietetic approaches (e.g., Mediterranean, low calories, protein-restricted, vegetarian diets, and gluten-free diet, GFD) have shown a certain efficacy in improve psoriasis cutaneous and systemic manifestations. In recent years, the existence of a wheat-related disorder in patients who do not suffer from CD or wheat allergy (WA) has been definitively ascertained and defined as Non-Celiac Wheat Sensitivity (NCWS). Its prevalence in the general population is unknown, but self-reported NCWS is around 10%. This condition is characterized by both GI and extraintestinal symptoms, which are triggered by wheat ingestion. In these patients, wheat ingestion might lead to alteration in intestinal permeability and gut microbiota and to systemic immune activation and inflammation. Based on the evidence of gut involvement in the pathogenesis and clinical manifestation of psoriasis, as well as on the ability of gluten/wheat to increase intestinal permeability, it could be hypothesized that gluten/wheat may represents one of the pathogenetic environmental factors of psoriasis and that its intake may be able to worsen symptoms in affected patients. The investigators hypothesize that a wheat-free diet (WFD) can reduce the inflammatory state and ameliorate the clinical symptoms in psoriasis patients. The successive clinical and immunologic reaction to the re-exposure to wheat ingestion, performed by an open challenge, will be also evaluated to confirm a wheat-dependent mechanism and to understand the underlining physiopathology.

Eligibility

Primary outcome measure(s)

• Self-perceived non-celiac wheat sensitivity (NCWS) questionnaire in psoriasis patients — Before enter the study.
  To identify psoriasis patients reporting a self-perceived NCWS; all patients will be asked to answer, consecutively, to a validated questionnaire for the self-assessment of wheat and other foods' intolerance. This is a questionnaire self-compiled by patients consisting of three sections: 1) general information (eg. age, sex, highest completed education level, etc.) 2) wheat-related symptoms (sore 0 = no symptoms, score = 1, symptoms after wheat intake; if score = 1 other question qualitatively inquire the symptoms evoked by wheat intake, eg. what kind of symptoms, how long patient perceive this problem, etc.); 3) other foods-related symptoms (score 0 = no symptoms, score 1 = symptoms after intake of other foods; if score = 1 other question qualitatively inquire the symptoms evoked by the intake of the specific food reported by the patients, eg. what kind of symptoms, how long patient perceive this problem, etc.)
• Effect of WFD plus CMPFD in changing symptoms of psoriasis patients as assessed by BSA — Start of the study (Day 0); 2 months of wheat elimination diet (Day 60).
  To assess the effect that a WFD plus CMPFD determines in symptoms of patients affected with psoriasis the following score will be used: Body Surface Area (BSA), representing the percentage of cutaneous area affected by psoriasis.
• Effect of WFD plus CMPFD in changing symptoms of psoriasis patients as assessed by Psoriasis Area Severity Index — Start of the study (Day 0); 2 months of wheat elimination diet (Day 60).
  To assess the effect that a WFD plus CMPFD determines in symptoms of patients affected with psoriasis the following score will be used: Psoriasis Area Severity Index (PASI), a composite evaluation for psoriasis severity, subscoring for erythema, induration, scaling, and percentage of body-surface area affected. The rating scale includes 4 levels: No Psoriasis, Mild Psoriasis, Moderate Psoriasis, and Severe Psoriasis.
• Effect of WFD plus CMPFD in changing symptoms of psoriasis patients as assessed by IGA — Start of the study (Day 0); 2 months of wheat elimination diet (Day 60).
  To assess the effect that a WFD plus CMPFD determines in symptoms of patients affected with psoriasis the following score will be used: Investigator's Global Assessment (IGA), a 5-point instrument for rating the clinician's impression of the overall severity of the psoriasis, from 0, clear skin, to 4, severe disease.
• Effect of WFD plus CMPFD in changing symptoms of psoriasis patients as assessed by GSRS — Start of the study (Day 0); 2 months of wheat elimination diet (Day 60).
  To assess the effect that a WFD plus CMPFD determines in symptoms of patients affected with psoriasis the following score will be used: Gastrointestinal Symptom Rating Scale (GSRS), assessment scale for irritable bowel syndrome-like and functional dyspepsia-like symptoms, providing for a score ranging from 15 to 60).
• Effect of WFD plus CMPFD in changing symptoms of psoriasis patients as assessed by Extraintestinal symptoms rating scale. — Start of the study (Day 0); 2 months of wheat elimination diet (Day 60).
  To assess the effect that a WFD plus CMPFD determines in symptoms of patients affected with psoriasis the following score will be used: Extraintestinal symptoms rating scale, a scoring system based on the symptoms most frequently observed in NCWS patients, providing for a score ranging from 9 to 34.
• Effect of WFD plus CMPFD in changing Quality of Life (QoL) of psoriasis patients. — Start of the study (Day 0); 2 months of wheat elimination diet (Day 60).
  To assess the effect that a WFD plus CMPFD determines in QoL of patients affected with psoriasis, both of the intervention and the control group. The following score will be used: Dermatology Life Quality Index (DLQI, a validated instrument to evaluate quality of life for skin disease, providing for a score ranging from 0 to 30 points, with higher scores indicating a greater effect on quality of life).

Trial sites (3)

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