In a young adult nursing student/CNA who works in a hospital and lives on a college campus, presenting with an acute rash on the elbows and ankles after spray‑tan use and shaving, could scabies be a differential diagnosis?

Scabies as a Differential Diagnosis in a College Nursing Student/CNA

Yes, scabies should absolutely be included in the differential diagnosis for this patient, despite not living in a dormitory, because her dual roles as a nursing student and hospital CNA create substantial occupational exposure risk through direct patient contact. 1, 2

Why Scabies Must Be Considered in This Clinical Context

High-Risk Occupational Exposure

• Healthcare workers, particularly CNAs who provide hands-on patient care, face significant scabies transmission risk through prolonged skin-to-skin contact during bathing, repositioning, and direct patient care activities. 1, 2
• Hospital and nursing home settings are explicitly identified as high-risk environments for scabies epidemics, with institutional outbreaks requiring treatment of entire at-risk populations. 1
• The patient's clinical role involves the exact type of "close personal contact" that CDC guidelines identify as the primary transmission route for scabies. 1, 2

Classic Clinical Presentation Features

• Scabies characteristically presents with intense pruritus that is worse at night, often appearing disproportionate to visible skin findings—a pattern that should prompt serious diagnostic consideration. 3
• The distribution on elbows and ankles is consistent with scabies, which classically affects finger webs, wrists, extensor surfaces of elbows and knees, waist, abdomen, buttocks, and genitals. 4
• The pathognomonic sign is the presence of burrows (thread-like papules), typically up to 1 cm in length, though the generalized hypersensitivity rash consists of erythematous macules and papules with excoriation. 5, 3

Timing and Alternative Explanations

• While the temporal association with spray-tan and shaving suggests contact or irritant dermatitis, scabies can coexist with or be misattributed to other triggers because sensitization to the mite takes several weeks in first-time infestations. 1, 6
• In patients with their first scabies infection, sensitization takes several weeks to develop, meaning the rash and pruritus may not appear until weeks after initial mite exposure—potentially coinciding with unrelated cosmetic procedures. 1

Diagnostic Approach to Confirm or Exclude Scabies

Key Historical Features to Elicit

• Ask specifically about: (1) intense nocturnal pruritus affecting multiple body regions except the head; (2) whether any household members, roommates, or close contacts are also itching; (3) recent exposure to patients with known or suspected scabies; (4) whether the itch seems out of proportion to visible findings. 3
• Inquire about any recent institutional scabies outbreaks at her hospital workplace, as healthcare facilities frequently experience epidemics. 1

Physical Examination Priorities

• Perform meticulous inspection of finger webs, volar wrists, lateral aspects of fingers, extensor elbows and knees, waist, navel, abdomen, buttocks, and genital areas for burrows or the characteristic papular eruption. 4
• Look for serpiginous burrows (the pathognomonic sign), which appear as thread-like papules typically up to 1 cm in length. 5, 3
• Examine for secondary bacterial infection (crusting, weeping, pustules), which commonly complicates scabies and increases morbidity. 7, 3

Confirmatory Testing

• Definitive diagnosis requires microscopic identification of scabies mites, eggs, or fecal pellets from skin scrapings of suspected burrows or papules. 6, 4
• Dermatoscopy (epiluminescence microscopy) is a newer technique that can aid in-office diagnosis without requiring laboratory processing. 6
• If clinical suspicion is high but microscopy is negative, empiric treatment is reasonable because the sensitivity of skin scraping is imperfect and depends on examiner skill. 5

When to Refer or Escalate

• Refer to dermatology if: (1) diagnostic uncertainty persists after initial evaluation; (2) the patient fails to respond to two courses of different scabicides; (3) crusted scabies is suspected; (4) the patient is immunocompromised. 3
• Notify hospital infection control and occupational health if scabies is confirmed, as all close patient contacts and coworkers within the preceding month require simultaneous examination and treatment to prevent institutional outbreak. 1

Critical Pitfalls to Avoid

• Do not dismiss scabies solely because the patient does not live in a dormitory—occupational healthcare exposure is an independent and well-established risk factor. 1, 2
• Do not attribute persistent, intense nocturnal pruritus to anxiety or psychogenic causes without first excluding scabies, especially in healthcare workers. 3
• Do not delay empiric treatment while awaiting confirmatory testing if clinical suspicion is high, as untreated scabies perpetuates transmission and increases secondary bacterial infection risk. 5, 7
• Do not fail to simultaneously treat all household members and close contacts within the past month, even if asymptomatic, as this is the most common cause of treatment failure and reinfection. 1, 2