The study will be a prospective evaluation of dapsone gel, 5% in patients with a clinical diagnosis of dermatitis herpetiformis. Active disease must occur on the patients' bilateral elbows or bilateral knees at the time of study enrollment. Active disease will be defined as five or more papules/pustules/vesicles on an extremity. Randomization of one of the patient's extremities (either one elbow or one knee) to the treatment group will occur at time of enrollment. Randomization will be in the sequence of right side assigned to odd numbered patients and left side assigned to even numbered patients. Thus, the first patient to be enrolled, patient number one, would be randomized to treatment on his or her right side. Depending on the site of active disease, he or she would apply topical dapsone gel, 5% to the right elbow or knee twice daily for the duration of the study.

No blinding of the patients or the PI will occur. The co-investigator will be blinded to whether the photographs presented to him at the end of the study are those of a treated or untreated extremity.

The patients will be screened for study enrollment in a private clinic room within the dermatology clinic at One Hundred Oaks. Patients will be presented with a study summary sheet and a consent form. They will be allowed to ask questions pertaining to the study protocol. Information provided to them will be that found in the study protocol alone. If desired, informed consent can be taken home with the patient to consider, and enrollment can be performed at a later date. In that instance, the patient would be brought back for an additional visit at the time of consent and study enrollment. Study enrollment and first treatment will be performed on the day of study consent. Digital photographs of each elbow or each knee (treatment and control) will be taken on the day of enrollment to serve as a baseline evaluation. The number of lesions (including papules, plaques and vesicles) will be recorded for the treatment and control elbow or knee. Measurements of each lesion will be taken and recorded as well. This data will be written in a chart and stored in the PI's notebook in a locked cabinet in the department of dermatology. Digital photographs will be printed out on the same day as the visit and placed in the notebook as well. Two copies of each photograph will be made. Each photograph will be assigned a letter, A through Z, based on a code for each patient. One copy of each set of photographs will also include the date. No patient identifiable features will be included in the photograph such as the face or eyes. Each photograph will be of the treated or control area only. The code to identify patient photographs will be assigned by the Data and Safety Monitor and kept in a separate locked cabinet. The code will be broken following the blinded evaluation of the photographs by co-investigator.

The patient will be given oral instructions regarding the application of topical dapsone gel, 5% by the PI on the day of enrollment. The PI will apply the first treatment to the randomized extremity during the first clinic visit. The patient will then remain in the treatment room for fifteen minutes to evaluate for any immediate adverse reaction. The PI will remain in the room with the patient. At the end of the fifteen minute evaluation, the patient will be sent home with written instructions for application and a 30gm tube of ACZONE™ (dapsone) Gel, 5%. Patients will apply the study drug to the indicated elbow or knee each morning and evening for the two weeks. They will return to the dermatology clinic in two weeks and be seen in a private clinic room by the PI for a follow up visit. At that time, photographs, lesion counts and measurements will be taken again, just as they were at the initial visit. The patient will be asked to report any adverse events at that time. Patients will be instructed to continue treatment and follow up in two weeks. The same parameters will be evaluated at the four week visit and again at the six week visit, which will be the completion of the study.

Patients will discontinue treatment after six weeks. The co-investigator will be presented will all photograph marked with the patient letter only. He will not know the sequence of the photographs or dates taken. He will then assign a number according to his subjective evaluation of the clinical photographs, while also being blinded to which elbow or knee was treated, right or left. The scores assigned will follow the criteria listed in the investigator's Dermatitis Herpetiformis Assessment Score. The code to the photographs will be broken after the completion of photograph evaluation. Photographs of a set will be matched to those with both letter and date to determine the scores in chronological order.

Six weeks after completion of treatment each patient will be contacted by phone and asked a series of five questions. That will conclude the study.