Derm Dx: Rectal rash preceded by pain in an elderly man

Herpes zoster results from reactivation of the varicella zoster virus that has remained dormant within the dorsal root ganglia.1 The condition is usually accompanied by a pre-eruptive phase lasting an average of 48 hours and characterized by pain, pruritus, and/or...

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Herpes zoster results from reactivation of the varicella zoster virus that has remained dormant within the dorsal root ganglia.¹ The condition is usually accompanied by a pre-eruptive phase lasting an average of 48 hours and characterized by pain, pruritus, and/or paresthesia.²

Diagnosis is often delayed until lesions appear. Herpes zoster lesions are characterized by slightly indurated erythematous patches and plaques in a dermal distribution followed by the appearance of grouped herpetiform vesicles. Pain may be mild to severe and usually abates within 2 weeks. Pain persisting for more than 30 days is classified as postherpetic neuralgia.³

Advanced age, weakened cell-mediated immunity, and diseases such as malignancy and chronic lung, renal, or hepatic disease are risk factors for herpes zoster.⁴ Involvement of the rectum is uncommon, and fewer than 10% of cases occur in sacral dermatomes.⁵

Antiviral agents such as valacyclovir and famciclovir hasten the resolution of herpes zoster lesions and decrease the severity of acute pain but do not reduce the risk for postherpetic neuralgia.⁶ The live attenuated herpes zoster vaccine is most effective in individuals between ages 50 and 59. In those age 70 or older, the efficacy is 38%, although the incidence of postherpetic neuralgia is lessened by 67%.⁷

Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College and an adjunct assistant professor of dermatology at the University of Pennsylvania Medical College. He practices dermatology in Hazleton, Pennsylvania.

References

1. Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. Fitzpatrick’s Dermatology in General Medicine. 8th ed. New York, NY: McGraw Hill Medical; 2012.
2. Goh CL, Khoo L. A retrospective study of the clinical presentation and outcome of herpes zoster in a tertiary dermatology outpatient referral clinic. Int J Dermatol. 1997;36(9):667-672.
3. Kost RG, Straus SE. Postherpetic neuralgia—pathogenesis, treatment, and prevention. N Engl J Med. 1996;335(1):32-42.
4. McDonald JR, Zeringue AL, Caplan L, et al. Herpes zoster risk factors in a national cohort of veterans with rheumatoid arthritis. Clin Infect Dis. 2009;48(10):1364-1371.
5. Costache C, Costache D. A study of the dermatomers in herpes zoster. Bulletin of the Transilvania University of Braşov. 2009;2(51):19-24.
6. Cohen JI. Herpes zoster. N Engl J Med. 2013;369(18):1766-1767.
7. Cohen JI. A new vaccine to prevent herpes zoster. N Engl J Med. 2015;372(22):2149-2150