Among 144 patients evaluated at the NIH between March 23, 1972, and April 14, 2010, for possible DH (Figure 1), 58 were excluded (40%). Of these 58, 13 patients did not have a medical chart available (22%), and 45 did not meet inclusion criteria (78%) (31 had negative IgA DIF findings; 5 had DH for <2 years; 8 had follow-up for <3 years; and 1 patient's age of onset was unavailable). Among the 86 patients included in the study sample, 26 patients had died but were included in the study (30%). Fourteen of the 26 deceased patients had DH at the time of their death, as noted in their medical charts, and the disease status of the remaining 12 was obtained from a living relative by telephone interview. Of the 60 living patients, 12 were seen in person at the NIH, and 48 were contacted by telephone follow-up. Most patients had taken sulfones (dapsone, 25-300 mg/d, or sulfoxone, 165-825 mg/d before 1990) or sulfapyridine (500 mg/d to 3 g/d) and were prescribed varying doses of these drugs during their disease course. Three patients had been treated with corticosteroids or anti-TNF therapy (etanercept) for concomitant problems. Characteristics of all study participants are listed in Table 1.