ABD - American Board of Dermatology Inflammatory Dermatoses Questions and Answers

Question 1

A 42-year-old male with severe plaque psoriasis and psoriatic arthritis has failed topical therapies and phototherapy. He has a positive tuberculin skin test and chest X-ray findings consistent with latent tuberculosis. Initiation of which of the following biologic agents would carry the highest risk of tuberculosis reactivation, thus mandating pretreatment?

Accepted Answer

Infliximab

Answer

Tumor necrosis factor-alpha (TNF-α) is critical for the formation and maintenance of granulomas that contain Mycobacterium tuberculosis. TNF-α inhibitors, such as infliximab, adalimumab, and etanercept, significantly increase the risk of reactivating latent tuberculosis by disrupting these granulomas. Therefore, screening and treatment for latent TB are mandatory before starting therapy with a TNF-α inhibitor. While other biologics carry some risk, it is most pronounced and well-established for the TNF-α inhibitor class.

Question 2

Loss-of-function mutations in the gene encoding which of the following proteins are the strongest known genetic risk factor for the development of atopic dermatitis?

Accepted Answer

Filaggrin

Answer

Filaggrin (filament aggregating protein) is a key structural protein essential for the formation and function of the stratum corneum. Loss-of-function mutations in the filaggrin gene (FLG) impair skin barrier function, leading to increased transepidermal water loss and enhanced penetration of allergens. This is the most significant and well-established genetic predisposition for atopic dermatitis.

Question 3

A biopsy from a pruritic, violaceous, polygonal papule on a patient's wrist is examined. Which constellation of histopathologic findings is most characteristic of lichen planus?

Accepted Answer

Hyperkeratosis, wedge-shaped hypergranulosis, sawtooth rete ridges, and a band-like lymphocytic infiltrate.

Answer

The classic histopathologic features of lichen planus include hyperkeratosis, wedge-shaped hypergranulosis, irregular acanthosis creating a 'sawtooth' appearance of the rete ridges, and a dense, band-like (lichenoid) lymphocytic infiltrate that obscures the dermo-epidermal junction. Apoptotic keratinocytes (Civatte bodies) are also commonly seen.

Question 4

A 23-year-old patient presents with an acute eruption. It began 10 days ago with a single 4 cm oval, salmon-colored plaque with a fine peripheral scale on her abdomen. This was followed by the development of numerous smaller, similar-appearing plaques oriented along cleavage lines on her back. What is the most likely diagnosis?

Accepted Answer

Pityriasis rosea

Answer

This is a classic clinical presentation of pityriasis rosea. The initial, larger lesion is known as the 'herald patch.' The subsequent eruption of smaller, oval plaques oriented along skin cleavage lines (Langer's lines) creates a characteristic 'Christmas tree' distribution on the back.

Question 5

A 65-year-old male develops widespread dusky macules, bullae, and severe mucosal erosions of the eyes and mouth 12 days after starting a new medication. A clinical assessment estimates epidermal detachment at 20% of the total body surface area. According to the consensus classification, what is the most accurate diagnosis?

Accepted Answer

Overlap SJS/Toxic epidermal necrolysis (TEN)

Answer

The classification of the SJS/TEN spectrum is based on the percentage of body surface area (BSA) with epidermal detachment. SJS is defined as <10% BSA detachment, TEN is >30% BSA detachment, and cases with 10-30% BSA detachment are classified as SJS/TEN overlap. With 20% involvement, this patient falls into the overlap category.

American Board of Dermatology (ABD) Practice Test

American Board of Dermatology (ABD) Practice Test

ABD - American Board of Dermatology Inflammatory Dermatoses Questions and Answers