The purpose of this study is to determine the anti-inflammatory effect of high-dose riboflavin supplementation on chronic plaque psoriasis. Psoriasis is a common chronic skin disorder that affects over 4 million people. There is no cure for psoriasis and treatment is directed at controlling patients' symptoms. Amongst patients with skin disease, there is significant interest in using complementary alternative medicine and vitamins to treat their disease. Previous human case reports suggest that riboflavin, commonly known as Vitamin B2, is clinically effective for the treatment of psoriasis; however, they were not conclusive. More recent human trials have shown that 400 mg of daily oral riboflavin is a safe and well-tolerated medication to administer to humans. For the purpose of this study, the riboflavin is used as an investigational drug.

The purpose of this investigation is to determine the anti-inflammatory effect of high-dose riboflavin supplementation on chronic plaque psoriasis. Up to fifty volunteers with chronic plaque psoriasis will be recruited for a double-blind, placebo-controlled 28 week prospective study with cross-over of both the intervention and control groups at the 12 week time mark. There will be a 4 week washout period when subjects crossover. Riboflavin will be dosed 400 mg by mouth daily versus placebo. Throughout the study the investigators will perform both clinical and laboratory assessments to measure response.

Inclusion Criteria:

• 18 years of age or older
• Good general health
• Willingness and ability to follow the protocol
• Signed Informed Consent Form, written and witnessed.
• Stable moderate to severe chronic plaque psoriasis involving 8% or greater total body surface area (TBSA).
• If subject is a woman of childbearing potential, she must have a negative pregnancy test at screening and agree to use a medically acceptable form of contraception during the screening and throughout the study.

Exclusion Criteria:

• Started using a topical steroid stronger than moderate strength, vitamin A or D analog preparations, or anthralin within 14 days of study drug initiation.

• Initiated a systemic medications, including biologic medication, or phototherapy within 180 days of study drug initiation.

• Prior or concurrent use of cyclophosphamide.

• Currently using sulfasalazine therapy.

• Known hypersensitivity to riboflavin.

• Enrolled in any other investigational device or investigational drug trial(s) or receipt of any other investigational agent(s) within 28 days of baseline visit.

• Presence of severe comorbidities such as, diabetes mellitus requiring insulin; congestive heart failure (CHF) of any severity or myocardial infarction or cerebrovascular accident or transient ischemic attack within 3 months of screening visit; unstable angina pectoris, uncontrolled hypertension [sitting systolic BP <80 mm Hg or > 160 or diastolic BP > 100 mm Hg], oxygen-dependent severe pulmonary disease, history of cancer within 5 years [other than resected cutaneous basal or squamous cell carcinoma of the skin or in situ cervical cancer].

• Any of the following hematologic abnormalities, confirmed by repeat test at least 1 week apart:

  1. White blood count <3,000/µL or >14,000/µL
  2. Lymphocyte count <1,000/µL
  3. Neutrophil count <1,5000/µL
  4. Platelet count <150,000/µL
  5. Hemoglobin<10 g/dL

• Liver function test aspartate aminotransferase (AST), alanine aminotransferase (ALT) or alkaline phosphatase (AlkP) results that are greater than or equal to 2 times the upper limit of normal (ULN).

• Serum creatinine ≥ to 2x the ULN.

• Known HIV-positive status or known history of any other immune-suppressing disease.

• Any current or past history of psychiatric disease that would interfere with ability to comply with study protocol or give informed consent.

• Had grade 3 or 4 adverse events or infections within 28 days before screening, or between screening visit and drug initiation.

• Evidence of any skin conditions other than psoriasis that would interfere with the evaluations of the effect of study medication on psoriasis.

• Presence of any condition or circumstances judged by the patient's physician, the investigator, or medically qualified study staff to render this clinical trial detrimental or otherwise unsuitable for the patient's participation.

• A history of non-compliance with other therapies.

• Females who are pregnant, lactating, planning on pregnancy during the study period, or unwilling to use FDA-approved method of birth control.

• A history of keloids or excessive scar formation or of healing poorly.

• A history of allergic reaction to local anesthetics, including lidocaine and epinephrine

Participants were followed for 32 weeks (12 weeks of treatment 1; 4 weeks of washout; 12 weeks of treatment 2; and 4 weeks of followup)