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Dermatitis herpetiformis (DH) is an autoimmune blistering skin disease associated with coeliac disease (gluten enteropathy). DH may be considered as a cutaneous manifestation of coeliac disease.
All forms of coeliac disease involve intolerance to the gliadin fraction of gluten found in wheat; there are IgA antibodies. In DH, IgA antibodies are deposited in the skin. Recent research suggests that coeliac patients with DH have a qualitatively different immune reaction in the intestinal mucosa than those that do not. This results in minimal clinical symptoms, allowing for increased gluten ingestion and cutaneous IgA deposition.
- For coeliac disease, UK prevalence is around 1%.
- DH is most common in Caucasians of northern European descent with a prevalence of 11.2 and an incidence of 0.98% per 100,000 people.
- There is a male:female preponderance of approximately 2:1.
- DH usually presents in the fourth decade but has been reported in children as young as 2 and in the elderly as old as 90.
DH is an intensely itchy bullous rash. It characteristically affects extensor surfaces, particularly the scalp, buttocks, elbows and knees. However, lesions can occur on any area of skin.
- The lesions are papules and blisters, up to 1 cm in diameter, which are extremely itchy. They arise on normal or reddened skin. Burning, stinging and intense pruritus can precede the appearance of new lesions.
- The severity can vary from week to week.
- Lesions rarely resolve without specific treatment.
There may also be symptoms of coeliac disease.
This is usually necessary to confirm the diagnosis. The microscopic appearance of DH is characteristic:
- The blister is subepidermal.
- Inflammatory cells group in the dermal papillae.
- Direct immunofluorescence reveals IgA immunoglobulin in dermal papillae.
These may show abnormalities due to gluten enteropathy; for example:
- Mild anaemia
- Folic acid deficiency
- Iron deficiency
Coeliac disease can usually be detected by autoantibody testing:
- IgA anti-tissue transglutaminase or IgA endomysial antibodies are highly specific and sensitive for untreated coeliac disease. They are also relevant to DH patients. IgA-epidermal transglutaminase 3 is likely to be the most specific immunocomplex in DH.
- Note that these tests can be falsely negative if the patient:
- Is already on a gluten-free diet.
- Has selective IgA deficiency, which is more common in coeliac disease patients than in the general population.Therefore it may be advisable to measure serum IgA levels to identify cases of IgA deficiency; or to test for IgG endomysial antibodies or IgG-tissue transglutaminase levels.
- A small proportion of patients with coeliac disease are tissue transglutaminase antibody-negative (0.4% in one series) and some are endomysial antibody-negative. Detection rates may be improved by combining both tests.
Other possible investigations
- A novel serological assay using deamidated gliadin-analogous fusion peptides (GAF3X) showed high diagnostic sensitivity in DH patients with coeliac disease.
- Histocompatibility antigen typing: HLA-DR-DQ genotyping is expensive but techniques are being developed to make this more cost-effective in the diagnosis of coeliac disease.
- Small bowel biopsy (may appear normal if on a gluten-free diet, or due to skip lesions in the bowel).
- Erythema multiforme
- Herpes gestationis
- Linear IgA bullous dermatosis
- Neurotic excoriations
- Papular urticaria
- Transient acantholytic dermatosis
A strict gluten-free diet is important in order to:
- Reduce the medication needed to control skin symptoms. It may be possible to discontinue dapsone when on a gluten-free diet for sufficient time.
- Reduce the associated enteropathy, improve nutrition and bone density.
- Possibly, reduce the risk of developing other autoimmune conditions and intestinal lymphoma.
- Dapsone is first choice and reduces the itch within a day or two. Cautions and blood monitoring requirements should be noted.
- For those intolerant or allergic to dapsone, the following may be used:
- Ultrapotent topical steroids
- Systemic steroids
- Ciclosporin, colchicines, heparin, tetracycline and nicotinamide are other treatments that have been tried with some benefit.
- Avoid drugs which exacerbate DH. These may include NSAIDs (though ibuprofen seems safe) and iodides.
Virtually all DH patients have coeliac disease, although it may be unnoticed.
Complications may arise from problems associated with coeliac disease. These include:
- Neurological problems - ataxia (gluten ataxia), peripheral neuropathy, epilepsy
- Cardiac problems - pericarditis and cardiomyopathy
- Osteoporosis and poor dental enamel
- Reduced fertility and recurrent miscarriage
- Abnormal LFTs
- Aphthous ulcers
- Possibly, other autoimmune conditions: thyroid disease, insulin-dependent diabetes mellitus, autoimmune hepatitis, Sjögren's syndrome, Addison's disease, atrophic gastritis and alopecia areata
- Non-Hodgkin's lymphoma - affects <1% of DH patients
- There may be a slightly increased risk of other cancers
Some of these problems may be improved by a gluten-free diet.
- Untreated, DH follows a prolonged course over years, with relapses and remissions.
- The prognosis is good, as DH responds well to diet and medication:
- About 80% of patients with dermatitis herpetiformis have good results from a gluten-free diet. The recovery rate varies and some patients can take up to four years to respond.
- It may take a year or more of this diet before medication for DH can be reduced.
- Some patients are able to stop dapsone completely with diet treatment.
Further reading & references
- Lorinczy K, Juhasz M, Csontos A, et al; Does dermatitis herpetiformis result in bone loss as coeliac disease does? A cross sectional study. Rev Esp Enferm Dig. 2013 Apr;105(4):187-193.
- Garcia-Manzanares A, Lucendo AJ; Dermatitis herpetiformis - What lies beneath the skin? Rev Esp Enferm Dig. 2013 Apr;105(4):183-186.
- Dermatitis herpetiformis; DermNet NZ
- Rivera E, Assiri A, Guandalini S; Celiac disease. Oral Dis. 2013 Oct;19(7):635-41. doi: 10.1111/odi.12091. Epub 2013 Mar 18.
- Cardones AR, Hall RP 3rd; Pathophysiology of dermatitis herpetiformis: a model for cutaneous manifestations of gastrointestinal inflammation. Immunol Allergy Clin North Am. 2012 May;32(2):263-74, vi. doi: 10.1016/j.iac.2012.04.006.
- Plotnikova N, Miller JL; Dermatitis herpetiformis. Skin Therapy Lett. 2013 Mar-Apr;18(3):1-3.
- Karpati S; Dermatitis herpetiformis. Clin Dermatol. 2012 Jan;30(1):56-9. doi: 10.1016/j.clindermatol.2011.03.010.
- Kumar V, Jarzabek-Chorzelska M, Sulej J, et al; Celiac disease and immunoglobulin a deficiency: how effective are the serological methods of diagnosis? Clin Diagn Lab Immunol. 2002 Nov;9(6):1295-300.
- Hopper AD, Cross SS, Hurlstone DP, et al; Pre-endoscopy serological testing for coeliac disease: evaluation of a clinical decision tool. BMJ. 2007 Apr 7;334(7596):729. Epub 2007 Mar 23.
- Emami MH, Karimi S, Kouhestani S, et al; Diagnostic accuracy of IgA anti-tissue transglutaminase in patients suspected of having coeliac disease in Iran. J Gastrointestin Liver Dis. 2008 Jun;17(2):141-6.
- Swallow K, Wild G, Sargur R, et al; Quality not quantity for transglutaminase antibody 2: the performance of an endomysial and tissue transglutaminase test in screening coeliac disease remains stable over time. Clin Exp Immunol. 2013 Jan;171(1):100-6. doi: 10.1111/cei.12000.
- Kasperkiewicz M, Dahnrich C, Probst C, et al; Novel assay for detecting celiac disease-associated autoantibodies in dermatitis herpetiformis using deamidated gliadin-analogous fusion peptides. J Am Acad Dermatol. 2012 Apr;66(4):583-8. doi: 10.1016/j.jaad.2011.02.025. Epub 2011 Aug 12.
- Lavant EH, Carlson J; HLA DR-DQ genotyping by capillary electrophoresis for risk assessment for celiac disease. Methods Mol Biol. 2013;919:297-307. doi: 10.1007/978-1-62703-029-8_26.
- Samasca G, Bruchental M, Butnariu A, et al; Difficulties in Celiac Disease Diagnosis in Children - A case report. Maedica (Buchar). 2011 Jan;6(1):32-5.
- Blistering skin diseases; DermNet NZ, 2013
- Parrish C; Dermatitis Herpetiformis:What Practitioners Need to Know, Practical Gastroenterology, 2012
- Van L, Browning JC, Krishnan RS, et al; Dermatitis herpetiformis: potential for confusion with linear IgA bullous dermatosis on direct immunofluorescence. Dermatol Online J. 2008 Jan 15;14(1):21.
- Asamoah V, von Coelln R, Savitt J, et al; The many faces of celiac disease. Gastroenterol Hepatol (N Y). 2011 Aug;7(8):549-54.
- Dermatitis herpetiformis; Coeliac UK
- Neuhausen SL, Steele L, Ryan S, et al; Co-occurrence of celiac disease and other autoimmune diseases in celiacs and their first-degree relatives. J Autoimmun. 2008 Sep;31(2):160-5. doi: 10.1016/j.jaut.2008.06.001. Epub 2008 Aug 8.
- Derikx MH, Bisseling TM; Untreated celiac disease in a patient with dermatitis herpetiformis leading to a small bowel carcinoma. Case Rep Gastroenterol. 2012 Jan;6(1):20-5. doi: 10.1159/000336066. Epub 2012 Jan 10.
- Coeliac UK
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Dr Naomi Hartree
Dr Laurence Knott
Dr Helen Huins