A 36-year-old man comes to the office due to a 2-month history of a pruritic rash over the elbows and knees. The patient has been using skin emollients, but the lesions have not improved. He also has a prolonged history of episodic abdominal discomfort, flatulence, and voluminous greasy stools. Cardiopulmonary examination is normal. The abdomen is soft and nontender. Skin examination shows a papulovesicular skin rash in groups with erosion and excoriations. Which of the following is most likely to be seen in this patient?

Question

A 36-year-old man comes to the office due to a 2-month history of a pruritic rash over the elbows and knees.  The patient has been using skin emollients, but the lesions have not improved.  He also has a prolonged history of episodic abdominal discomfort, flatulence, and voluminous greasy stools.  Cardiopulmonary examination is normal.  The abdomen is soft and nontender.  Skin examination shows a papulovesicular skin rash in groups with erosion and excoriations.  Which of the following is most likely to be seen in this patient?

Quizplus · Accepted Answer

11ec160b_38f2_7dd1_9249_fbe2dbbfc4f1_MD0001_00 Dermatitis herpetiformis (DH) is characterized by erythematous pruritic papules, vesicles, and bullae that appear symmetrically on the extensor surfaces (eg, elbows, knees), upper back, and buttocks. Herpetiformis refers to the resemblance of the clustered vesicles to those of herpes simplex. DH is characterized histologically by microabscesses containing fibrin and neutrophils at the dermal papillae tips. The overlying basal cells become vacuolated, and coalescing blisters form at the tips of the involved papillae. Immunofluorescent imaging shows deposition of IgA at the dermoepidermal junction. The pathogenesis of DH is associated with that of celiac disease. Following absorption of dietary gluten, gliadin is deaminated by tissue transglutaminase in a process involving formation of covalent crosslinks between the two. Because of this, the subsequent immune response against gliadin also targets tissue transglutaminase, leading to the production of IgA and IgG tissue transglutaminase autoantibodies. In the skin, these antibodies cross-react with epidermal transglutaminase, and the resulting inflammation leads to the characteristic manifestations of DH. The majority of patients with DH exhibit the small-bowel histologic findings of celiac disease, which include: (Choice A) Ulcerative colitis is characterized by mucosal inflammation, crypt abscesses (neutrophils in glandular lumen), and ulcerations. Common dermal associations include erythema nodosum, pyoderma gangrenosum, and psoriasis. The papulovesicular rash seen in this patient is not consistent with any of these entities. (Choice B) IgG-mediated skin disruption occurs in pemphigus vulgaris and bullous pemphigoid. These conditions are characterized by large bullae and ulcerations that are not confined to the extensor surfaces. Pemphigus vulgaris may involve the pharynx and esophagus, but neither condition is associated with steatorrhea. (Choice D) Elevated urinary porphyrin levels (ie, uroporphyrin, heptacarboxyl porphyrin) are seen in porphyria cutanea tarda. This condition is characterized by skin fragility and blistering lesions in sun-exposed areas. Steatorrhea would be unexpected. (Choice E) Insulin resistance occurs in type 2 diabetes mellitus, which can be associated with acanthosis nigricans and necrobiosis lipoidica diabeticorum. Although celiac disease and DH are associated with other autoimmune disorders, including type 1 diabetes, there is no association with type 2 diabetes. Educational objective: Dermatitis herpetiformis is characterized by erythematous pruritic papules, vesicles, and bullae that appear symmetrically on extensor surfaces. It is strongly associated with celiac disease, a disorder characterized histologically by small intestinal intraepithelial lymphocytosis, crypt hyperplasia, and villous atrophy.

A 36-Year-Old Man Comes to the Office Due to a 2-Month