A 61-year-old man comes to the office due to a painful rash on his face for the past 3 days. The patient has no other medical conditions and takes no medications. He is a retired schoolteacher and lives with his wife. Skin examination findings are shown in the exhibit.
The remainder of the physical examination shows no abnormalities. Which of the following events most likely immediately preceded the appearance of skin rash in this patient?

Question

A 61-year-old man comes to the office due to a painful rash on his face for the past 3 days.  The patient has no other medical conditions and takes no medications.  He is a retired schoolteacher and lives with his wife.  Skin examination findings are shown in the exhibit. 
 The remainder of the physical examination shows no abnormalities.  Which of the following events most likely immediately preceded the appearance of skin rash in this patient?

Quizplus · Accepted Answer

11ec160b_387d_9c3e_9249_d7c82f4b175c_MD0001_00 This patient has a crusted vesicular rash in a dermatomal distribution consistent with shingles (herpes zoster). Shingles is caused by reactivation of varicella-zoster virus (VZV), a double-stranded DNA virus of the herpesvirus family. Primary VZV infection occurs most commonly in childhood. Inoculation in the nasopharyngeal mucosa is followed by migration of the virus to the regional lymphatics. Subsequent dermatotrophic migration produces a diffuse vesicular rash associated with fever, malaise, and pharyngitis (chickenpox). Then, the virus migrates via sensory nerves to cranial nerve and dorsal spinal ganglia, where it lies dormant for decades. Most patients who have had primary chickenpox do not develop recurrent diffuse disease. Over time, however, waning cell-mediated immune function allows reactivation of the virus, which typically spreads down a single spinal nerve to cause a painful, erythematous, vesicular rash in a dermatomal distribution. The primary risk factor for reactivation is increasing age; other factors can include malignancy, autoimmune disease, and immune-suppressing therapy. The varicella vaccine is recommended for prevention of primary disease in children, women of childbearing age, adults with sustained risk of exposure, and household contacts of immunocompromised hosts. Zoster vaccine is recommended for adults age ?50 and reduces the risk of reactivation. (Choice A) Colonization of the skin by transient flora (eg, Staphylococcus aureus, Candida species, gram-negative bacilli) occasionally leads to clinical disease, especially following antibiotic exposure (eg, vaginal candidiasis). However, VZV does not remain on the surface of the skin for prolonged periods. (Choices B and C) Primary VZV infection (ie, chickenpox) can be acquired by direct contact or airborne aerosol from patients with active chickenpox or zoster lesions. However, primary VZV infection causes diffuse lesions; lesions in a dermatomal distribution are seen only with reactivation from sensory ganglia. (Choice E) Declining VZV-specific immunity increases the risk of reactivation. However, the immune response to VZV is primarily based on cell-mediated, rather than humoral (ie, antibodies), factors. Educational objective: Primary varicella-zoster virus infection (chickenpox) occurs most commonly in childhood. Subsequently, the virus migrates to the sensory ganglia, where it lies dormant for decades. Over time, waning cell-mediated immunity allows reactivation of the virus, which spreads down a single nerve to cause a painful, erythematous, vesicular rash in a dermatomal distribution. __________ References: Molecular mechanisms of varicella zoster virus pathogenesis. (http://www.ncbi.nlm.nih.gov/pubmed/24509782)

A 61-Year-Old Man Comes to the Office Due to a Painful