A 56-year-old woman comes to the office for evaluation of a leg ulcer. The patient bumped her left leg on a chair 2 weeks ago and noticed painful papules at the injury site several days later. The lesions rapidly enlarged and opened, causing worsening pain and drainage. The ulcer progressively enlarged despite the use of topical antiseptics. The patient has a history of rheumatoid arthritis and does not use tobacco, alcohol, or illicit drugs. Temperature is 37.2 C (99 F), blood pressure is 130/78 mm Hg, and pulse is 86/min. Physical examination shows a tender ulcer on the lower left extremity, as shown in the exhibit. There are no other lesions. Which of the following is the most likely cause of this patient's skin condition?

Question

A 56-year-old woman comes to the office for evaluation of a leg ulcer.  The patient bumped her left leg on a chair 2 weeks ago and noticed painful papules at the injury site several days later.  The lesions rapidly enlarged and opened, causing worsening pain and drainage.  The ulcer progressively enlarged despite the use of topical antiseptics.  The patient has a history of rheumatoid arthritis and does not use tobacco, alcohol, or illicit drugs.  Temperature is 37.2 C (99 F), blood pressure is 130/78 mm Hg, and pulse is 86/min.  Physical examination shows a tender ulcer on the lower left extremity, as shown in the exhibit.  There are no other lesions.  Which of the following is the most likely cause of this patient's skin condition?

Quizplus · Accepted Answer

11ec25c8_d8ba_5675_bc81_d7a49f402581_MD0003_00 This patient's skin ulcer is consistent with pyoderma gangrenosum (PG). PG is a form of neutrophilic dermatosis that starts as an inflammatory papule, pustule, or nodule and progresses to form an expanding ulcer with a purulent or fibrinous base and an irregular, violaceous border. PG can present as a single or as multiple lesions, usually on the trunk or lower extremities. Nearly 30% are triggered by local trauma (ie, pathergy). The risk of PG is increased in patients who have an underlying systemic inflammatory disorder. Common associations include inflammatory bowel disease, autoimmune arthropathies (eg, rheumatoid arthritis), and hematologic conditions (eg, acute myeloid leukemia). PG is diagnosed clinically after excluding other diagnoses (eg, infection, cutaneous cancers). Biopsy of the ulcer margin is recommended and typically shows a mixed cellular infiltrate with dermal and epidermal necrosis. Surgical debridement is usually avoided due to the potential of inducing pathergy; most lesions respond to treatment with local or systemic glucocorticoids. (Choice A) Cutaneous small vessel vasculitis typically presents with nonblanching, raised petechiae or purpura. Scattered bullae and small ulcers may form, but large, isolated ulcers and pathergy are not typical and are more suggestive of PG. raised petechiae or purpura (Choice B) Ecthyma gangrenosum is a skin infection most frequently due to Pseudomonas aeruginosa. It presents as hemorrhagic pustules with surrounding erythema that rapidly progress to form necrotic ulcers. Patients typically have systemic symptoms (eg, fever), but focal pain is less prominent. necrotic ulcers (Choice D) Thromboangiitis obliterans is characterized by pain and ulceration in the distal extremities, primarily the digits. This disorder is rare in nonsmokers, and patients are typically age <45. (Choice E) Venous insufficiency ulcers are often found at the malleoli, are associated with only mild pain, and are generally seen in the setting of chronic stasis changes (ie, brawny discoloration, dermal atrophy). Venous insufficiency ulcers Educational objective: Pyoderma gangrenosum is characterized by rapidly progressive, painful ulcers with a purulent base and violaceous border, often following local trauma (pathergy). Many patients have underlying systemic inflammatory disorders (eg, rheumatoid arthritis, inflammatory bowel disease). The diagnosis is made clinically after excluding other etiologies, usually with skin biopsy. Treatment is with corticosteroids. References: Pyoderma gangrenosum - a guide to diagnosis and management. (http://www.ncbi.nlm.nih.gov/pubmed/31092515)

A 56-Year-Old Woman Comes to the Office for Evaluation of a Leg