What treatment is recommended for a painful rash suspected to be herpes zoster?

Treatment for Suspected Herpes Zoster with Painful Ear Lesions

For this 47-year-old patient with suspected herpes zoster presenting as painful vesicular lesions on the ear, initiate oral acyclovir 800 mg five times daily for 7-10 days immediately while awaiting swab confirmation, as treatment is most effective when started within 48-72 hours of rash onset. 1

Immediate Antiviral Therapy

• Start oral acyclovir 800 mg five times daily for 7-10 days without waiting for laboratory confirmation, as clinical diagnosis based on the characteristic unilateral vesicular rash in a dermatomal distribution (tragus and external canal) is sufficient, especially given the recent exposure to a relative with clinical shingles 1

• Treatment initiated within 72 hours of rash onset shortens time to lesion scabbing, healing, and complete cessation of pain, with greatest benefit when started within the first 48 hours 1

• In immunocompetent patients with localized cutaneous zoster, acyclovir reduces duration of viral shedding, duration of new lesion formation, and prevalence of localized zoster-associated neurologic symptoms (paresthesia, dysesthesia, hyperesthesia) 1

Pain Management Strategy

• Continue paracetamol 500 mg as needed for acute pain control 1

• For severe pain not controlled with paracetamol alone, consider adding a nonsteroidal anti-inflammatory drug or short-term opioid analgesics during the acute phase 2, 3

• Monitor closely for development of postherpetic neuralgia (PHN), defined as pain persisting more than 3 months after rash healing, which is more common in adults over 50 years and requires a longer-term pain management strategy 2, 3

Topical Management

• Continue crystaderm (fusidic acid) twice daily as prescribed to prevent secondary bacterial infection, particularly important given the presence of open vesicles that create portals for bacterial entry 4

• Staphylococcus aureus is the most frequently detected infectious agent in secondarily infected skin lesions, and bacterial swabs should be obtained if signs of infection develop (yellow crusts, discharge, failure to respond to treatment) 4

• The hydrogen peroxide 1% cream currently being used can continue for gentle antiseptic cleansing 4

Critical Monitoring Parameters

• Reassess in 2-3 days when swab results return to confirm herpes zoster diagnosis and ensure treatment response 1

• Watch for warning signs requiring immediate escalation: spread beyond the dermatomal distribution, involvement of the eye (herpes zoster ophthalmicus), severe pain uncontrolled by oral analgesics, or signs of secondary bacterial infection 4

• If lesions involve the tip of the nose (Hutchinson's sign) or any periocular area, urgent ophthalmology referral is mandatory to prevent vision-threatening complications 2

Important Caveats for This Patient

• The patient's smoking status increases risk of delayed healing and complications—strongly reinforce smoking cessation counseling, as this directly impacts wound healing and immune function 5

• Adequate hydration must be maintained during acyclovir therapy to prevent renal dysfunction, particularly important as acyclovir can crystallize in renal tubules 1

• The close contact with a relative diagnosed with clinical shingles is notable but does not change management, as herpes zoster results from reactivation of latent varicella-zoster virus rather than new infection 2, 3

When Treatment Fails or Complications Arise

• If no improvement after 2-3 days of acyclovir, consider treatment failure due to acyclovir-resistant varicella-zoster virus (rare in immunocompetent hosts) or incorrect diagnosis 1

• Development of disseminated lesions (more than 20 lesions outside the primary dermatome) or systemic symptoms suggests possible immunocompromise and requires immediate reassessment and consideration of intravenous acyclovir 4, 1

• For severe acute pain or early signs of PHN development, consider early referral to pain management or neurology for multimodal pain control strategies including gabapentin or pregabalin 2, 3

Preventive Counseling

• After resolution of this acute episode, the patient should receive counseling about the recombinant zoster vaccine (RZV/SHINGRIX), which is highly effective at preventing future episodes of herpes zoster and is recommended for adults, though typically starting at age 50 6

• Explain that herpes zoster is not contagious in the same way as chickenpox, but the vesicular fluid contains live virus that can cause chickenpox in susceptible individuals (those never infected or vaccinated), so lesions should be covered until fully crusted 3, 7