A 65-year-old woman comes to the office due to a rash on both thighs for the past 3 weeks. The rash started as areas of redness with pruritus. In the past week, the pruritus has intensified, and numerous blisters developed on the medial thighs. An over-the-counter oral antihistamine has not provided relief. There are no mouth sores, eye discomfort, weight loss, or diarrhea. Medical history includes hypertension, hypercholesterolemia, and early Parkinson disease. Temperature is 37 C (98.6 F), blood pressure is 125/83 mm Hg, and pulse is 76/min. Skin examination is shown in the exhibit. Punch biopsies are performed. Which of the following is the most appropriate initial therapy pending biopsy results?

Question

A 65-year-old woman comes to the office due to a rash on both thighs for the past 3 weeks.  The rash started as areas of redness with pruritus.  In the past week, the pruritus has intensified, and numerous blisters developed on the medial thighs.  An over-the-counter oral antihistamine has not provided relief.  There are no mouth sores, eye discomfort, weight loss, or diarrhea.  Medical history includes hypertension, hypercholesterolemia, and early Parkinson disease.  Temperature is 37 C (98.6 F), blood pressure is 125/83 mm Hg, and pulse is 76/min.  Skin examination is shown in the exhibit.  Punch biopsies are performed.  Which of the following is the most appropriate initial therapy pending biopsy results?

Quizplus · Accepted Answer

11ec25c8_d372_6826_bc81_f368d6acd6de_MD0003_00 This patient with pruritic bullae most likely has bullous pemphigoid (BP), an autoimmune blistering disorder. BP is most common in patients age >60 and has an increased incidence in those with neurologic disorders (eg, Parkinson disease). As in this patient, a prodromal phase of pruritic, eczematous or urticarial-like lesions may last weeks to months, followed by the development of tense bullae, which may rupture to form erosions. BP can be diffuse or localized, involving the trunk, extremities, axillae, and inguinal folds. Unlike pemphigus vulgaris, in BP, mucous membrane involvement is rare, and pruritus, not pain, accompanies the rash. erosions Whether empiric therapy is initiated to alleviate severe pruritus, the diagnosis must be confirmed with skin biopsy (ie, light microscopy, direct immunofluorescence) because therapy is often chronic and can involve agents with significant toxicity (eg, systemic corticosteroids). Serology for antibodies against bullous pemphigoid antigens (ie, hemidesmosomes) can further support the diagnosis. First-line treatment for BP is a high-potency topical corticosteroid (eg, clobetasol), which is effective even for extensive disease. If systemic therapy is preferred, oral doxycycline or an oral corticosteroid can be used, although the latter is not more effective than topical corticosteroids. (Choices A and B) Dermatitis herpetiformis associated with celiac disease is an autoimmune cutaneous eruption caused by gluten sensitivity, but the eruption is not typically accompanied by a prodromal phase, and papulovesicular lesions, not bullae, are characteristic. A combination of a gluten-free diet and dapsone (also a second-line corticosteroid-sparing agent for BP that is not routinely used) can quickly induce remission. Dermatitis herpetiformis (Choice C) Oral valacyclovir is used to treat herpes zoster, which presents with grouped vesicles on erythematous bases in a unilateral dermatomal distribution. The rash is associated with burning, neuropathic pain, rather than pruritus. grouped vesicles on erythematous bases (Choice E) Tinea corporis presents with a pruritic, annular, scaly plaque that can sometimes be accompanied by vesicles and bullae (ie, tinea corporis bullosa). However, this patient's bullae arose from urticarial patches that lack features of tinea corporis. annular, scaly plaque urticarial patches Educational objective: Bullous pemphigoid is an autoimmune blistering disorder that typically occurs in patients age >60. It is characterized by pruritic, tense bullae preceded by a prodrome of eczematous or urticarial rash. The diagnosis requires skin biopsy. First-line treatment is a high-potency topical corticosteroid, which is effective even for extensive disease. References: Bullous pemphigoid. (http://www.ncbi.nlm.nih.gov/pubmed/31090818)

A 65-Year-Old Woman Comes to the Office Due to a Rash