This book describes Dermatitis Herpetiformis, Diagnosis and Treatment and Related DiseasesDermatitis herpetiformis is a rare but continual immunobullous disease that has been linked to celiac disease, a gluten-sensitive enteropathy.The name herpetiformis is obtained from the tendency for blisters to happen in clusters, similar to herpes simplex.Dermatitis herpetiformis is not caused by viral infection.Dermatitis herpetiformis is also termed Duhring-Brocq diseaseDermatitis herpetiformis (DH) is a very itchy rash comprising bumps and blisters.The rash is persistent (long-term).IncidenceDH normally starts in people age 20 and older.Children can occasionally be involved.Dermatitis herpetiformis mainly involves Caucasians aged 15–40 years but may happen in those younger or older and in other races.It is observed in both men and women.There is a 2:1 male-to-female ratio.More females under the age of 20 are involved than males.There is a genetic predilection with a link with human leukocyte antigens (HLA) DQ2 and DQ8.Some patients have a personal or family history of other autoimmune diseases such as thyroid disease, pernicious anemia, type 1 diabetes, vitiligo, Addison disease and alopecia areataCausesThe precise cause is not known.In spite of the name, it is not linked to the herpes virus.DH is an autoimmune disorder.There is a strong link between DH and celiac disease.Celiac disease is an autoimmune disorder that produces inflammation in the small intestine from eating gluten.People with DH also have allergy to gluten, which produces the skin rash.About 25% of people with celiac disease also have DH.Dermatitis herpetiformis and celiac disease are caused by intolerance to the gliadin fraction of gluten present in wheat, rye and barley.Gluten precipitates formation of IgA antibodies and an autoimmune process that aims the skin and intestines.In celiac disease, gluten produces intestinal inflammation causing diarrhea, tiredness, weight loss and abdominal discomfort.The main percentage (> 90%) of patients with dermatitis herpetiformis also have gluten-sensitive enteropathy.Gastrointestinal symptoms can be mild to severe; some patients stay symptom-free.Around 15–25% of celiac patients have concomittent dermatitis herpetiformis.These patients are likely to have a more severe intestinal pathology compared to those with mainly dermatitis herpetiformis.Symptoms are:1. Extremely itchy bumps or blisters, most often on the elbows, knees, back, and buttocks.2. Rashes that are normally the same size and shape on both sides.The rash can similar to eczema.3. Scratch marks and skin erosions instead of blisters in some people.Most people with DH have injury to their intestines from eating gluten.DiagnosisIn most cases, a skin biopsy and direct immunofluorescence test of the skin are performed.Skin biopsy is usually necessary to confirm dermatitis herpetiformis.TreatmentStrict adherence to gluten-free diet reduces this rare but serious long-term complicationGluten-free diet for life is strongly recommended in patients with dermatitis herpetiformis, as it:1. Reduces the requirement for medication to control dermatitis herpetiformis2. Improves associated gluten-sensitive enteropathy3. Enhances nutrition and bone density4. May reduce the risk of developing other autoimmune conditions5. May reduce the risk of intestinal lymphomaDapsone is the treatment of choice for dermatitis herpetiformis, as it usually reduces itch within 3 days.If intolerant or allergic to dapsone, these may be useful:1. Ultra-potent topical steroids2. Systemic steroids3. Sulfapyridine4. RituximabImmuno-suppressants are less effective.TABLE OF CONTENTIntroductionChapter 1 Dermatitis HerpetiformisChapter 2 CausesChapter 3 SymptomsChapter 4 DiagnosisChapter 5 TreatmentChapter 6 PrognosisChapter 7 PemphigusChapter 8 Celiac DiseaseEpilogue