MKSAP: 40-year-old woman with a symmetrically distributed rash

Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 40-year-old woman is evaluated for a 4-month history of symmetrically distributed, severely pruritic, grouped erosions on her elbows, knees, back, and buttocks. The skin lesions began as red spots that developed into papules and then vesicles, which broke down as she scratched them. She reports normal bowel habits. She has no other medical problems and takes no medications.

A biopsy reveals neutrophilic infiltrate at the tips of the dermal papillae causing subepidermal separation. Diffuse immunofluorescence shows granular deposition of IgA at the dermal papillae.

Which of the following is the most appropriate management option for this patient?

A) Cyclosporine
B) Dapsone
C) Dapsone and a gluten-free diet
D) Intravenous immune globulin
E) Lactose-free diet

MKSAP Answer and Critique

The correct answer is C) Dapsone and a gluten-free diet. This item is available to MKSAP 15 subscribers as item 32 in the Dermatology section.

Most, if not all, patients with dermatitis herpetiformis have gluten sensitivity, even when they have no evidence of enteropathy. Treatment with a gluten-free diet is successful in greater than 70% of patients with dermatitis herpetiformis, but excellent adherence to the diet is required for a minimum of 3 to 12 months. In the interim, initial suppression of symptoms with dapsone is usually necessary for more rapid relief of symptoms.

Continued compliance with the gluten-free diet will allow a decrease in the dapsone, and it can often be discontinued. A gluten-free diet treats the cause, rather than the symptoms, of the disease. Dapsone treatment requires careful monitoring. Hemolysis is the most common side effect of treatment and may be severe in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Pretesting for G6PD deficiency prior to initiating therapy with dapsone is generally recommended. Additional adverse reactions include toxic hepatitis, cholestatic jaundice, psychosis, and both motor and sensory neuropathy. Patients with dermatitis herpetiformis and their first-degree relatives are at increased risk for other autoimmune diseases, including thyroid disease, rheumatoid arthritis, and lupus erythematosus.

There is no role for cyclosporine, a lactose-free diet, or intravenous immune globulin in the treatment of dermatitis herpetiformis.

Key Point

  • Treatment with a gluten-free diet is successful in greater than 70% of patients with dermatitis herpetiformis, even in the absence of symptomatic enteropathy.

Learn more about ACP’s MKSAP 16.

This content is excerpted from MKSAP 15 with permission from the American College of Physicians (ACP). Use is restricted in the same manner as that defined in the MKSAP 15 Digital license agreement. This material should never be used as a substitute for clinical judgment and does not represent an official position of ACP. All content is licensed to KevinMD.com on an “AS IS” basis without any warranty of any nature. The publisher, ACP, shall not be liable for any damage or loss of any kind arising out of or resulting from use of content, regardless of whether such liability is based in tort, contract or otherwise.

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