Derm Dx: Itchy Rash on Outer Arm - Clinical Advisor

Derm Dx: Itchy Rash on Outer Arm

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A 42-year-old woman presents for evaluation of an itchy rash that affects her outer arms and buttocks. The condition was first diagnosed while she was living in the Dominican Republic approximately 4 years ago. At that time, she was treated with dietary modification (gluten-free diet) and oral medication, which resulted in resolution of her symptoms. She returned to the United States several months ago without a prescription for her oral medication and is now experiencing a flare. The patient states that her health is good. She denies history of diabetes, hypertriglyceridemia, gastrointestinal complaints, or renal disease.

Dermatitis herpetiformis (DH) is an uncommon autoimmune blistering disease characterized by papulovesicles that are symmetrically distributed on the extensor surfaces of the extremities and buttocks. Virtually all patients with the disorder complain of moderate to severe pruritus.1  The condition was...

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Dermatitis herpetiformis (DH) is an uncommon autoimmune blistering disease characterized by papulovesicles that are symmetrically distributed on the extensor surfaces of the extremities and buttocks. Virtually all patients with the disorder complain of moderate to severe pruritus.1 

The condition was first identified by the Philadelphia dermatologist Louis Duhring in 1884.2 Most prevalent in individuals of Irish and Scandinavian descent, DH peaks in middle age and is associated with human leukocyte antigen DQ2 and DQ8 haplotypes.3 The underlying pathophysiology results from immunologic stimulation of intestinal mucosa by gluten consumption.4,5 This results in neutrophilic recruitment and deposition of immunoglobulin A (IgA) in the dermal papillae, a hallmark of the disease that was first recognized in 1969.6    

The diagnosis of DH is based primarily on results of direct immunofluorescence of a skin biopsy sample that demonstrates IgA deposits. Autoantibodies against endogenous enzyme tissue transglutaminase are frequently detected in serum. Oral dapsone, which was serendipitously found to benefit DH in 1950, is still considered a cornerstone of therapy when strict dietary avoidance of gluten cannot be achieved.7 The risk of non-Hodgkin lymphoma is increased among individuals with DH.8

Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Reunala TL. Dermatitis herpetiformis. Clin Dermatol. 2001;19(6):728-736.

2. Duhring L. Dermatitis herpetiformis. JAMA. 1884;III(9):225-229.

3. Bolotin D, Petronic-Rosic V. Dermatitis herpetiformis. Part I. Epidemiology, pathogenesis, and clinical presentation. J Am Acad Dermatol. 2011;64(6):1017-1024.

4. Plotnikova N, Miller JL. Dermatitis herpetiformis. Skin Therapy Lett. 2013;18(3):1-3.  

5. Antiga E, Maglie R, Quintarelli L, et al. Dermatitis herpetiformis: novel perspectives. Front Immunol. 2019;10:1290.

6. van der Meer JB. Granular deposits of immunoglobulins in the skin of patients with dermatitis herpetiformis. An immunofluorescent study. Br J Dermatol. 1969;81(7):493-503.  

7. Esteves J, Brandao FN. Effect of sulfonamides and sulfones on Duhring’s disease. Clin Lat. 1952;2(1):34-39.

8. Grainge MJ, West J, Solaymani-Dodaran M, Card TR, Logan RF. The long-term risk of malignancy following a diagnosis of coeliac disease or dermatitis herpetiformis: a cohort study. Aliment Pharmacol Ther. 2012;35:730-739.

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