Pruritic rash develops after a change in diet


  • CA0611DermClin1

A man aged 33 years presented with a one-week history of blisters on his hands and a severely itchy rash on his scalp, arms, and groin. No allergies or significant medical or surgical history were reported.

The patient noted a change in diet in the week prior to onset of symptoms due to the Passover holiday traditions. Physical exam revealed small hemorrhagic bullae on the bilateral dorsal hands and erythematous papules, scattered papulovesicles, and extensive erosions on dorsal arms, upper back, posterior neck, and inguinal region. A punch biopsy was performed.

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Dermatitis herpetiformis Hematoxylin and eosin (H&E) stain of the biopsy revealed hyperkeratosis, numerous neutrophils, and neutrophilic karyorrhexis within the dermis. In addition, neutrophils were present within dermal papillae with edema. Fluorescent staining for immunoglobulin (Ig) deposits revealed 1+ granular IgA...

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Dermatitis herpetiformis

Hematoxylin and eosin (H&E) stain of the biopsy revealed hyperkeratosis, numerous neutrophils, and neutrophilic karyorrhexis within the dermis. In addition, neutrophils were present within dermal papillae with edema. Fluorescent staining for immunoglobulin (Ig) deposits revealed 1+ granular IgA and complement C3 within the tips of dermal papillae. These findings are consistent with a diagnosis of dermatitis herpetiformis (DH).

DH is a chronic, relapsing autoimmune skin disease formerly known as Duhring’s disease, named for Dr. Louis Duhring, who first described the condition in 1884. DH is strongly associated with gluten-sensitive enteropathy (GSE), more commonly known as celiac disease. Gluten sensitivity typically presents as GSE with symptoms of abdominal pain, bloating, weight loss, and diarrhea. In select individuals, GSE presents as isolated DH or GSE in combination with DH.

Almost all patients with DH have some endoscopic evidence of enteropathy.1 In a majority of patients, however, the intestinal pathology is mild and does not give rise to the typical GI symptoms of malabsorption.

DH presents with herpetiform (grouped) and symmetrically distributed papules, urticarial plaques, vesicles, papulovesicles, or bullae on the extensor surfaces of the elbows and knees, scalp, nuchal area, and buttocks. In addition, there may be linear petechial or purpuric macules and papules on the volar aspect of the fingers2 or pigmented spots over the lumbosacral region. The mucous membranes are rarely involved. Because the lesions are intensely pruritic, the patient often presents with extensive secondary excoriations, erosions, crusting, and no discernible primary lesions.

DH typically presents in the teenage to young adult years with an equal male-to-female incidence. It is more common in whites, particularly those of northern European ancestry and is rare in people of African or Asian descent.

The pathophysiology of DH is believed to include a genetic predisposition for gluten sensitivity combined with a diet high in gluten. Both DH and GSE are associated with an increased expression of haplotypes HLA-B8, HLA-DR3, and HLA-DQ2. Gluten ingestion in genetically predisposed individuals triggers the formation of IgA antibodies to tissue transglutaminase. These antibodies cross-react with epidermal transglutaminase.3 The IgA and epidermal transglutaminase complexes are then deposited in the papillary dermis, triggering an immunologic cascade. The characteristic lesions of DH are thus the end result of an immunologic response to dietary gluten.

The differential diagnosis includes the primary bullous disorders (bullous pemphigoid, pemphigus, linear IgA dermatosis, epidermolysis bullosa acquisita, porphyria cutanea tarda), scabies, arthropod reaction, Sweet syndrome, and neurotic excoriations.

Diagnosis is based on a history of gluten sensitivity, clinical presentation, and skin biopsy. Although a history of gluten intolerance will help narrow the differential diagnosis, many patients presenting with DH deny any symptoms of GI disturbance. To confirm the diagnosis, a skin biopsy should be collected from lesional skin for H&E stain and from perilesional skin for direct immunofluorescence (DIF). Primary H&E finding in DH is a subepithelial blister with neutrophils in the dermal papillae. The DIF finding of IgA deposition in a granular pattern at the basement membrane with accentuation in dermal papillae is confirmatory. Some patients also demonstrate deposition of complement C3 at the basement membrane. Immunofluorescence is thought to be a sensitive and specific assay in DH, and there are no other known diseases with this pattern of immunofluorescence.4

Recommended serologic workup for gluten sensitivity includes serum IgA endomysial antibodies, IgA anti-tissue transglutaminase antibodies, IgA and IgG anti-gliadin antibodies, and total IgA level. For patients with evidence of DH, testing for anti-transglutaminase antibodies should be done.5

Although there is no cure for DH, control is attainable with adherence to a strict gluten-free diet. Patients should be referred to a gastroenterologist for a complete GSE workup. As in treatment for celiac disease, avoidance of all dietary wheat, barley, and rye is a lifelong goal. A strict gluten-free diet restores normal mucosal morphology6 and improves skin disease within several months.7 Levels of circulating antibodies also tend to normalize. Any gluten reintroduced into the diet, even in minute amounts, will likely trigger an outbreak of new skin lesions.

Diet therapy is often not sufficient. Many patients are unable to remain committed to a strict gluten-free lifestyle. For others, skin lesions significantly impair quality of life, and additional treatment is requested. Dapsone, an antiparasitic, is typically the first-line therapy. Although symptomatic improvement of skin lesions is usually seen within hours, dapsone has no effect on the GI mucosal pathology. Second-line treatments include sulfapyridine, colchicines, cyclosporine, and prednisone.

There is a small increased incidence of thyroid disease, pernicious anemia, and diabetes in patients with DH. Studies also have shown an increased incidence of non-Hodgkin lymphoma8 and GI cancers,9 particularly small-bowel lymphoma. A strict gluten-free diet has been proven to decrease the risk of developing these diseases.

This patient was educated regarding his biopsy results and the association of dermatitis herpetiformis with celiac disease. The disease was likely triggered by the patient’s increased intake of Passover matzoh, a wheat-rich bread. He was referred to a gastroenterologist for further workup and educated regarding a gluten-free diet. He was started on clobetasol (Temovate) cream to alleviate the pruritus of the skin lesions.

The patient returned for follow-up several weeks later with worsening of skin lesions and requested additional therapy. He conceded that his diet was not entirely gluten-free. The risks of increased malignancy with gluten intake and side effects of dapsone therapy were reviewed. After a baseline complete blood count, comprehensive metabolic profile, and G6PD screen were all within normal limits, the patient was started on dapsone 50 mg, and the dosage was gradually increased. After several months of dapsone therapy and adherence to gluten-free diet, the patient was able to taper off the dapsone and reported no skin symptoms.

Ms. Stern is a family nurse practitioner at Advanced Dermatology & Skin Surgery, P.C., in Lakewood, N.J. The author has no relationships to disclose relating to the content of this article.

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1. Gawkrodger DJ, McDonald C, O’Mahony S, Ferguson A. Small intestinal function and dietary status in dermatitis herpetiformis. Gut. 1991;32:377-382.

2. McGovern TW, Bennion SD. Palmar purpura: an atypical presentation of childhood dermatitis herpetiformis. Pediatr Dermatol. 1994;11:319-322.

3. Sárdy M, Kárpáti S, Merkl B, et al. Epidermal transglutaminase (TGase 3) is the autoantigen of dermatitis herpetiformis. J Exp Med. 2002;195:747-757.

4. Warren SJ, Cockerell CJ. Characterization of a subgroup of patients with dermatitis herpetiformis with nonclassical histologic features. Am J Dermatopathol. 2002;24:305-308.

5. Kumar V, Jarzabek-Chorzelska M, Sulej J, et al. Tissue transglutaminase and endomysial antibodies-diagnostic markers of gluten-sensitive enteropathy in dermatitis herpetiformis. Clin Immunol. 2001;98:378-382.

6. Garioch JJ, Lewis HM, Sargent SA, et al. 25 years’ experience of a gluten-free diet in the treatment of dermatitis herpetiformis. Br J Dermatol. 1994;131:541-545.

7. Andersson H, Mobacken H. Dietary treatment of dermatitis herpetiformis. Eur J Clin Nutr. 1992;46:309-315.

8. Collin P, Pukkala E, Reunala T. Malignancy and survival in dermatitis herpetiformis: a comparison with coeliac disease. Gut. 1996;38:528-530.

9. Askling J, Linet M, Gridley G, et al. Cancer incidence in a population-based cohort of individuals hospitalized with celiac disease or dermatitis herpetiformis. Gastroenterology. 2002;123:1428-1435.

All electronic documents accessed May 15, 2011.

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