Disease course
Dermatitis herpetiformis, if not treated, runs a chronic relapsing course with exacerbations followed by phases in which signs and symptoms are less severe.[1]Antiga E, Maglie R, Quintarelli L, et al. Dermatitis herpetiformis: novel perspectives. Front Immunol. 2019 Jun 11:10:1290.
https://www.frontiersin.org/articles/10.3389/fimmu.2019.01290/full
http://www.ncbi.nlm.nih.gov/pubmed/31244841?tool=bestpractice.com
After a gluten-free diet is adopted, most patients slowly improve until they achieve complete remission. However, cutaneous manifestations may last for months to years after starting a gluten-free diet.[61]Rai S, Kaur A, Chopra CS. Gluten-free products for celiac susceptible people. Front Nutr. 2018 Dec 17:5:116.
https://www.frontiersin.org/articles/10.3389/fnut.2018.00116/full
http://www.ncbi.nlm.nih.gov/pubmed/30619866?tool=bestpractice.com
In these patients, treatment with dapsone is often able to induce remission in just a few days, although the treatment should be prolonged until all skin lesions have resolved as early discontinuation may cause relapse.[62]Mansikka E, Hervonen K, Kaukinen K, et al. Gluten challenge induces skin andsmall bowel relapse in long-term gluten-free diet-treated dermatitis herpetiformis. J Invest Dermatol. 2019 Oct;139(10):2108-14.
https://www.jidonline.org/article/S0022-202X(19)31485-X/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/30998982?tool=bestpractice.com
Re-introduction of gluten
Dermatitis herpetiformis is nearly always associated with coeliac disease and a lifelong gluten-free diet should be maintained.[63]Antiga E, Caproni M, Pierini I, et al. Gluten-free diet in patients with dermatitis herpetiformis: not only a matter of skin. Arch Dermatol. 2011 Aug;147(8):988-9.
http://www.ncbi.nlm.nih.gov/pubmed/21844467?tool=bestpractice.com
Almost all patients with long-lasting remission will experience a relapse if they re-introduce gluten into their diet. In one study, 10 out of 86 patients with dermatitis herpetiformis did not show relapses of cutaneous manifestations, although their intestinal status was not assessed.[49]Paek SY, Steinberg SM, Katz SI. Remission in dermatitis herpetiformis: a cohort study. Arch Dermatol. 2011 Mar;147(3):301-5.
https://jamanetwork.com/journals/jamadermatology/fullarticle/426768
http://www.ncbi.nlm.nih.gov/pubmed/21079050?tool=bestpractice.com
More recently, 20 patients with dermatitis herpetiformis re-introduced gluten into their diet after complete remission of the disease. At 1 year, all but one showed skin or intestinal relapse.[62]Mansikka E, Hervonen K, Kaukinen K, et al. Gluten challenge induces skin andsmall bowel relapse in long-term gluten-free diet-treated dermatitis herpetiformis. J Invest Dermatol. 2019 Oct;139(10):2108-14.
https://www.jidonline.org/article/S0022-202X(19)31485-X/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/30998982?tool=bestpractice.com
Mortality
The life expectancy of people with dermatitis herpetiformis appears to be increased compared with that of the general population and that of people with coeliac disease.[64]Hervonen K, Alakoski A, Salmi TT, et al. Reduced mortality in dermatitis herpetiformis: a population-based study of 476 patients. Br J Dermatol. 2012 Dec;167(6):1331-7.
http://www.ncbi.nlm.nih.gov/pubmed/22708883?tool=bestpractice.com
[65]Viljamaa M, Kaukinen K, Pukkala E, et al. Malignancies and mortality in patients with coeliac disease and dermatitis herpetiformis: 30-year population-based study. Dig Liver Dis. 2006 Jun;38(6):374-80.
http://www.ncbi.nlm.nih.gov/pubmed/16627018?tool=bestpractice.com
The increased life expectancy rates compared with the general population may be explained by a number of reasons, including strict adherence to a gluten-free diet, and lower levels of smoking and hypercholesterolaemia in people with dermatitis herpetiformis.[64]Hervonen K, Alakoski A, Salmi TT, et al. Reduced mortality in dermatitis herpetiformis: a population-based study of 476 patients. Br J Dermatol. 2012 Dec;167(6):1331-7.
http://www.ncbi.nlm.nih.gov/pubmed/22708883?tool=bestpractice.com
Complications that may occur in patients with coeliac disease and may lead to death, such as lymphoma, although reported, are very rare in patients with dermatitis herpetiformis and the risk may be minimised by following a gluten-free diet.[66]Collin P, Pukkala E, Reunala T. Malignancy and survival in dermatitis herpetiformis: a comparison with coeliac disease. Gut. 1996 Apr;38(4):528-30.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1383109
http://www.ncbi.nlm.nih.gov/pubmed/8707082?tool=bestpractice.com