Predictive Factors of Post-Herpetic Neuralgia in Patients with Acute Herpes Zoster

ABSTRACT

BACKGROUND: Post-Herpetic Neuralgia(PHN) is the most common and serious complication of herpes zoster(H-Z). Especially in the elderly, intractable chronic pain is caused by PHN and it affects the quality of life severely. The study examined the predictive factors of PHN for its prevention and treatment. METHODS: 691 cases of patients with herpes zoster who visited department of dermatology were studied of Kwang Ju Christian Hospital during the five years from Jan. 1991 to Dec. 1995 Retrospective chart review was used to compare occurrence of PHN according to age, sex, residential area of patients, inpatients or outpatients status, nerve dermatome, interval of treatment, methods of treatment associated conditions and duration of PHN. The authors compared the incidence of patients with PHN and patients with H-Z according to above variables. For statistical analysis, we used Chi-square and t-test through SPSS/PC+ (P<0.05). RESULTS: The incidence of PHN was 22.9% (159/691) and increased with age. The incidence of patients under 60 years of age was 16.5%, more than 60 was 30.7% (P<0.05). There was no statistical significance concerning sex, residential area of patients, dermatome, method of treatment, associated conditions in the incidence of PHN compared to patients with H-Z. The significant difference In the incidence of PHN was shown between inpatients and outpatients status(20.5%, 27.3% respectively) (P<0.05). Anatomical site of PHN of the highest incidence was the opthalmic branch of trigeminal nerve(27.1%), followed by cervical(26.0%), thoracic(24.4%) and sacral(22.2%) in order of sequence. Associated conditions or diseases of PHN were observed in 80 patients(24.7%) including hypertension(39.5%), tuberculosis(39.3%), malignancy (34.5%), COPD(33.3%), Chronic hepatitis(22.7%), DM(15.4%). The interval between the onset of H-Z and the initiation of treatment showed that significant difference in the incidence of PHN was on the fourth day with less than and more than 4 days showing 18.5% 25.1% respectively(P<0.05). CONCLUSIONS: The important factors affecting the incidence of PHN were interval between the onset of H-Z and the initiation of treatment age and inpatients or outpatients status. The methods of treatment(acyclovir or steroid), sex, residential area of patients, associated conditions and nerve distribution were not significant factors.