CPC: The case of the scattered red rashes

• Which of the following is the most appropriate next step in the management of this patient?

  A 32-year-old female is evaluated in the Medtigo Medical Clinic for a 3-month history of progressively worsening eruptions of waxing and waning pruritic red rashes with scattered groups of small pimple-like bumps and blisters anatomically located exclusively on both upper extremities and both lower extremities. The patient reports the symptoms initially started a little over three months ago as mildly pruritic slightly red rashes which seemed to suddenly develop overnight on the extensor surfaces of both forearms, elbows, and knees and spontaneously self-resolved after a few days of mild itching and scratching. Several days to a week later, the same symptoms would suddenly manifest and spontaneously self-resolve after a few days. The patient admits that she did not think too much of the transient, intermittently recurring and self-resolving mildly pruritic red rashes and began taking over-the-counter oral diphenhydramine which provided symptomatic relief of the itching associated with the rashes. The patient then reports that after about eight or nine weeks of experiencing similar recurring and spontaneously resolving mildly pruritic red rashes, she noticed her symptoms rapidly becoming progressively worse in frequency, duration, severity of pruritus, and appearance with the visible eruption of scattered groups of small pimple-like bumps and blisters within the pruritic red rashes located on the extensor surfaces of both forearms, elbows, and knees. The patient finally states the worsening skin eruptions quickly became so intensely pruritic and an unsightly source of embarrassment despite trying numerous over-the-counter oral antihistamines and skin clearing anti-itch ointments with little if any noticeable improvements that she started to feel helpless and overly self-conscious about her skin condition which prompted her to seek professional medical care.

  After a full 10-point review of systems, the patient has no other complaints other than the waxing and waning intensely pruritic red rashes with multiple scattered groups of small pimple-like bumps and blisters on the extensor surfaces of both forearms, elbows, and knees. Her medical history is notable for one healthy full-term male child born six years ago via routine vaginal delivery without any peri-procedural complications. Her medical history is otherwise unremarkable. Her current medications which she only started taking less than three months ago are over-the-counter oral diphenhydramine and over-the-counter 1% hydrocortisone anti-itch topical cream. With the exception of her recent use of over-the-counter medications for the past three months, she normally takes no regular medications. To the best of her knowledge, she has no known allergies. She does not consume alcohol, smoke cigarettes, chew tobacco, or use recreational drugs. She has been married for eight years and is employed as an executive systems engineer for NASA’s Applied Physics Laboratory. She denies any prior history of similar symptoms, any family history of similar symptoms, any recent sick contacts, any dietary changes over the past several years, any recent outdoor activities such as camping, or any history of ever traveling outside of the northeastern region of the United States. She has a younger brother with Type 1 diabetes mellitus, an older sister with system lupus erythematosus, and a second older sister with Hashimoto’s thyroiditis. Her mother has rheumatoid arthritis and irritable bowel syndrome with constipation. Her father has psoriasis, osteoarthritis, gout, and hypertension. Both of her parents are originally from Northern Europe and both immigrated to the United States over four decades ago for academia and work. The rest of the patient’s medical history, social history, and family history is non-contributory.

  On physical examination, vital signs are normal. Height is 5’6” (167.6 cm), weight is 130 lbs (58.9 kg), and body mass index is 21.0 kg/m². Skin examination reveals polymorphic clusters of diffuse erythematous papules, vesicles, and excoriations symmetrically distributed over the extensor surfaces of bilateral forearms, elbows, and knees which seem to be intensely pruritic as the patient repeatedly scratches the affected skin areas during most of the clinical appointment and examination. Otherwise, the remainder of the physical exam is unremarkable.  

• Much to the dismay of the clinician, the finalized pathology report of the histopathologic analysis and direct immunofluorescence staining of the patient’s skin biopsies was unable to provide a definitive diagnosis. However, the finalized pathology report findings have narrowed the differential diagnosis to several likely medical conditions. Considering the overall clinical picture, which of the following medical conditions is the most likely leading diagnosis?

• While not clearly definitive, the results of histopathologic analysis and direct immunofluorescence staining test of the patient’s skin biopsies have narrowed the differential diagnosis to several likely medical conditions with some diagnoses being more likely than others. If the leading diagnosis is most likely dermatitis herpetiformis, which of the following is the most appropriate next best step in providing the strongest supportive evidence to assist in confirming the leading diagnosis of dermatitis herpetiformis?

Given the results of the serology lab tests in conjunction with the skin biopsy findings and the overall clinical picture, a firmly established diagnosis of dermatitis herpetiformis is made by the clinician. Which of the following is the primary treatment method for this particular medical condition?

The results from the appropriate laboratory tests reveal the following:

• The major aspect of treating dermatitis herpetiformis is fundamentally based on strict adherence to a lifelong gluten-free diet. In addition to implementing a strict lifelong gluten-free diet, which of the following is considered by most healthcare professionals to be the first-line medication of choice for the treatment of skin lesions and acute symptoms associated with dermatitis herpetiformis?

• Due to the well-known side effects of oral Dapsone treatment, the most recent published guidelines on the management of dermatitis herpetiformis recommend that patients who are to be treated with oral Dapsone should undergo several clinical tests to establish a baseline level and regular scheduled tests to continue monitoring for the possibility of the patient developing some of oral Dapsone’s well documented side effects. According to the most recent published guidelines on the management of dermatitis herpetiformis, the overall consensus recommends oral Dapsone as the first-line medication of choice. Due to the well-known potential side effects of oral Dapsone, the overall consensus of the published guidelines also recommends that patients who are to be treated with oral Dapsone should have several clinical tests performed before initiating oral Dapsone treatment and at regularly scheduled intervals throughout the course of oral Dapsone treatment. Which of the following clinical tests is not included in the recommended list of tests to be performed in patients before initiating oral Dapsone treatment and at regular intervals during oral Dapsone treatment?

• Many published studies have documented an increased association between patients diagnosed with dermatitis herpetiformis and other immunologically-based medical conditions. Due to the increased incidence of certain immunologic-based medical conditions in patients diagnosed with dermatitis herpetiformis, the most recent published guidelines on the management of dermatitis herpetiformis recommend routine screening for which of the following two most commonly associated immunologically-based medical conditions in patients diagnosed with dermatitis herpetiformis?

• Prior to initiating oral Dapsone treatment in patients with dermatitis herpetiformis, the most recent published guidelines on the management of dermatitis herpetiformis recommend that patients be tested for a specific biochemistry-related enzymopathy/disorder due to the possibility of oral Dapsone treatment inducing acute hemolytic anemia. For this specific biochemistry-related enzymopathy/disorder, which of following is the most likely mechanism underlying the pathogenesis of Dapsone-induced acute hemolytic anemia in patients with a variant susceptible to this particular reaction?