Peer Reviewed


Herpes Zoster

Dee Wee Lim, MD

Meenu Jindal, MD
Clemson University, Greenville, South Carolina

Jindal M. Herpes zoster. Consultant. 2015;55(5).


A 63-year-old woman presented with severe pain on the right side of her back for about 3 to 4 days duration. She described the pain as “burning and stabbing,” which is localized in right lower thoracic and upper lumbar area. She rubbed, massaged, and used a heating pad, but didn’t get much relief. She was unable to say anything about the rash or eruptions, as she never tried to see her back in the mirror and lives by herself. 

Discussion. Herpes zoster typically affects people older than 60 years, secondary to decreased varicella-zoster vaccine-specific cell-mediated immunity. Besides increased age, predisposing factors are cancer chemotherapy and immunosuppression. Classically, herpes zoster is characterized by an acute onset, sharp, radicular pain and skin eruption of grouped vesicles on an erythematous base (Figure 1). Chest (thoracic dermatomes) is the most common cutaneous site affected followed by face (trigeminal dermatome).1,2 Pain is often accompanied with pruritus, decreased sensation, and allodynia within the affected dermatomes. In more than 90% of cases, pain precedes the skin eruption by days to a week. Postherpetic neuralgia is the most common cause of morbidity in patients older than 60 years. It is generally considered pain that persists after the resolution of skin healing or pain more than 30 days to 3 to 6 months from the onset of the rash.3,4

Erythema ab igne is the skin's manifestation of chronic exposure to low levels of infrared heat (Figure 2). This disease was fairly common when many households relied on wood-burning stoves for heat.5 Interestingly, in the past 10 to 15 years, the heat sources have begun to mirror modern technology and convenience. There have been numerous reports of laptop-induced erythema ab igne on the thighs and even a case attributed to microwave popcorn.6,7

Clinically, erythema ab igne presents as a reticulated hyperpigmentation, and the distribution of skin involvement should mirror the heat source in question. The precise pathophysiology is not known, but microscopic changes include epidermal atrophy, vasodilation, and dermal deposition of melanin and hemosiderin.8 The eruption must be differentiated from livido reticularis, which occurs with diseases such as leukocytoclastic vasculitis. Treatment of erythema ab igne is aimed at removal of the heating source. Most importantly, the physician should inquire about the reason for exposure. The majority of patients with erythema ab igne are experiencing chronic pain, which may rarely be an indicator of an underlying malignancy.5 In severe or nonresolving cases, regular monitoring of permanent skin changes is advised because of the possibility of malignant degeneration in the affected areas.9,10

Outcome of the case. A diagnosis of thoracolumbar back pain was considered, but in view of presence of lesions, patient’s age and nature of pain, our team made the empiric diagnosis of herpes zoster and started treatment with Valtrex and neurontin. When we followed-up with the patient 2 weeks later, her symptoms were much improved. The vesicles were scabbed and healing, and though the reticular rash was still present, it was better. Patient admitted to continued use of heating pad; we increased neurontin and advised to decrease the use of heating pad.


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  2. McCrary ML, Severson J, Tyring SK. Varicella zoster virus. J Am Acad Dermatol. 1999;41(1):1-14.
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  5. Tan S, Bertucci V. Erythema ab igne: an old condition new again. CMAJ. 2000;162(1):77-78.
  6. Riahi R, Cohen P. Laptop-induced erythema ab igne: report and review of the literature. Dermatol Online J. 2012;18(6):5. 
  7. Donohue K, Nahm W, Badiavas E, et al. Hot pop brown spot: erythema ab igne induced by heated popcorn. J Dermatol. 2012;29(3):172-173.
  8. Smith M. Environmental and sports-related skin diseases. In: Bolognia J, Jorizzo J, Rapini R, eds. Dermatology. Vol 2. 2nd ed. St. Louis, MO: Mosby Elsevier; 2008:1355-1356. 
  9. Howe NR, Bader RS: Erythema ab igne. In: Demis DJ, ed. Clinical Dermatology. Philadelphia, PA: Lippincott; 1998. 
  10. Arrington JH III, Lockman DS. Thermal keratoses and squamous cell carcinoma in situ associated with erythema ab igne. Arch Dermatol. 1979;115(10):1226-1228.