What is the management for an HIV-positive adult on antiretroviral therapy (ART) presenting with itching and hives around a bite wound one week after the bite?

Management of Itching with Hives Around a Bite Wound in HIV Patient on ART

Immediate Assessment: Rule Out Severe Cutaneous Adverse Reactions

The priority is to exclude Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), or DRESS syndrome, which require immediate hospitalization. 1, 2

• Check for mucosal involvement (mouth ulcers, conjunctivitis, genital lesions), blistering, skin exfoliation, or epidermal detachment 1, 2
• Measure temperature—fever >39°C indicates severe hypersensitivity requiring immediate drug cessation 1, 2
• Assess for systemic symptoms: lymphadenopathy, hepatitis, or other organ involvement suggesting DRESS syndrome 1, 2
• Calculate body surface area involvement: <10% suggests SJS, 10-30% overlap syndrome, >30% TEN 1

Most Likely Diagnosis: Localized Allergic Reaction to Bite

This presentation is most consistent with a localized hypersensitivity reaction to the bite itself, not antiretroviral-induced drug hypersensitivity. 1, 2

• Antiretroviral hypersensitivity typically occurs within 1-6 weeks of starting therapy, not after stable treatment 1, 2
• Rash or fever occurring >3 months after ART initiation is almost always due to another cause 1
• Localized urticaria around a bite wound one week post-injury suggests delayed-type hypersensitivity to bite antigens 2, 3

Immediate Management Algorithm

Step 1: Wound Care and Local Treatment

• Wash the bite area with soap and water 1
• Apply topical hydrocortisone 1% cream to affected areas 3-4 times daily 4
• Use topical emollients to prevent xerosis, which is common in HIV patients and exacerbates pruritus 1, 5

Step 2: Systemic Antipruritic Therapy

• Prescribe non-sedating oral antihistamines (cetirizine 10 mg daily or loratadine 10 mg daily) for symptomatic relief 1, 2
• Avoid sedating antihistamines in elderly patients due to fall and cognitive impairment risk 2

Step 3: Consider HIV-Specific Pruritus Management

• If pruritus persists despite standard treatment, consider indomethacin 25 mg three times daily orally, which has proven more effective than sedating antihistamines for HIV-associated pruritus 1, 6
• Monitor for gastric intolerance with indomethacin use 1, 6
• Consider gastroprotection with proton pump inhibitors in high-risk patients 6

Laboratory Workup

Obtain baseline studies to assess for systemic involvement and rule out alternative diagnoses: 2

• Complete blood count (check for eosinophilia suggesting DRESS or parasitic infection) 1
• Comprehensive metabolic panel (assess liver function for drug-induced hepatotoxicity) 1, 2
• HIV viral load (degree of pruritus in HIV often correlates with viral load) 1, 5

Exclude Alternative Diagnoses

Scabies

• Always consider scabies in HIV patients, which can present with severe pruritus and minimal skin signs 1
• If suspected, treat with permethrin 5% cream applied from neck down, washed off after 8-14 hours 1

Pediculosis

• Examine for lice or nits if pruritus extends beyond bite area 1
• Treat with permethrin 1% cream rinse applied for 10 minutes if confirmed 1

Drug Hypersensitivity

• Review all medications started within the past 6 weeks, including over-the-counter drugs and herbal remedies 1, 2
• Discontinue any recently added medications if drug reaction suspected 1, 2

Critical Pitfalls to Avoid

• Never rechallenge with a suspected causative agent if drug hypersensitivity is confirmed—reactions occur sooner and can be fatal 1, 2
• Never use prophylactic corticosteroids or antihistamines when restarting medications known to cause rash 2, 3
• Do not apply caustic agents (bleach) or inject antiseptics into the wound 1
• Avoid expressing fluid by squeezing the wound, as this does not reduce infection risk 1

Monitoring and Follow-Up

• Monitor weekly until symptoms resolve 2
• Return immediately if fever develops, mucosal involvement appears, blistering occurs, or systemic symptoms emerge 1, 2, 3
• If no improvement after 2 weeks of appropriate treatment, refer to dermatology 2
• Consider infectious disease consultation if pruritus is generalized and persistent, as this may indicate inadequate HIV control 1, 5

When to Continue vs. Discontinue ART

Continue current ART regimen unless there is evidence of severe cutaneous adverse reaction with systemic involvement. 1

• Mild localized reactions around a bite wound do not warrant ART discontinuation 1, 7
• Only discontinue ART if mucosal involvement, blistering, fever >39°C, or systemic symptoms develop 1, 2
• Patients can sometimes be treated through mild-to-moderate rash not accompanied by fever or organ involvement 1