A 45-year-old man comes to the office due to recurrent, painful skin lesions in the right axilla for the past 6 months. The patient has no other medical history and takes no medication. He smokes a pack of cigarettes every day and works as a roofer. Vital signs are normal. Examination reveals tender, subcutaneous nodules in the right axilla and other findings as shown in the exhibit.
The remainder of the examination is normal. Which of the following is the most likely cause of the condition?

Question

A 45-year-old man comes to the office due to recurrent, painful skin lesions in the right axilla for the past 6 months.  The patient has no other medical history and takes no medication.  He smokes a pack of cigarettes every day and works as a roofer.  Vital signs are normal.  Examination reveals tender, subcutaneous nodules in the right axilla and other findings as shown in the exhibit.  
The remainder of the examination is normal.  Which of the following is the most likely cause of the condition?

Quizplus · Accepted Answer

11ec160b_38f7_adf8_9249_0b445a4a792c_MD0001_00 This patient has hidradenitis suppurativa (HS), which is characterized by painful, deep-seated nodules and scar formation in the axillae, groin, and medial thighs. The pathogenesis of HS begins with the occlusion of folliculopilosebaceous units caused by keratinocyte hyperproliferation and abnormal keratinocyte differentiation. Mechanical stress (eg, friction in intertriginous areas) then leads to follicular rupture and the release of proinflammatory contents. Contributing factors include tobacco use, immune dysregulation, hormonal factors (eg, excessive androgen effect), and bacterial colonization/infection. HS is a chronic, recurring condition with progressive formation of draining abscesses, sinus tracts (formed by epithelial stem cells released from follicular rupture), comedones (from significant follicular damage), and extensive fibrosis. In contrast to common furuncles and carbuncles, which usually resolve completely with drainage and antibacterial therapy, HS may persist and recur despite months of antibiotic therapy. (Choice A) It was once thought that HS is a suppurative disease involving the apocrine, not the eccrine, sweat glands. However, current understanding supports follicular occlusion as the cause. (Choice B) Colonization of hair follicles by Cutibacterium acnes triggers the inflammatory response seen in acne vulgaris, which typically begins in adolescence and primarily affects the face, chest, and upper back. In contrast, HS involves the intertriginous regions, with symptoms usually beginning after age 18. Early HS lesions are typically sterile but later become colonized or infected with gram-positive, gram-negative, and anaerobic bacteria. (Choice C) Squamous cell carcinoma can occasionally arise in areas affected by HS due to chronic inflammation. However, it typically presents as a well-demarcated, scaly papule or plaque, features absent in this patient's lesion. Educational objective: Hidradenitis suppurativa results from the occlusion of folliculopilosebaceous units. Subsequent follicular rupture and inflammation form painful nodules and abscesses, which may progress to sinus tracts, scars, and comedones with chronic, recurrent disease. __________ References: Hidradenitis suppurativa: rapid evidence review. (http://www.ncbi.nlm.nih.gov/pubmed/31674740)

A 45-Year-Old Man Comes to the Office Due to Recurrent