Thirty-six women and fourteen men diagnosed with varicella were enrolled in the study (Table 1). The diagnosis of varicella was mainly based on clinical manifestation and was confirmed by the Tzanck test, which was performed in 46 patients (92%) with 42 (91.3%) positive. A VZV antigen test was performed in four patients (8%) and all had positive results. The mean age (SD) was 32.7 (11.5) years, ranging from 18.5 to 63.3 years. Twelve patients (24%) were healthcare professionals. Almost all patients lived in the central region of Thailand, and 67.4% of them lived in Bangkok.
Table 1
Characteristics of 50 adult patients diagnosed with varicella visiting the dermatology clinic at Siriraj hospital, Jan 2018 - Jun 2022
Characteristics | N (%) |
Sex | |
Female | 36 (72.0) |
Male | 14 (28.0) |
Age, years Mean ± SD | 32.7 ± 11.4 |
min, max | 18.5, 63.3 |
Age of first episode, years Mean ± SD | 28.2 ± 14.3 |
min, max | 0.3, 63.3 |
Highest Education | |
Never been in school | 1 (2.0) |
Primary school | 3 (6.0) |
Secondary school | 8 (16.0) |
Vocationalist | 8 (16.0) |
Bachelor degree or higher | 30 (60.0) |
Occupation | |
Healthcare worker | 12 (24.0) |
Non-healthcare worker | 38 (76.0) |
Residential area | |
Bangkok | 35 (70.0) |
Central (other than Bangkok) | 13 (26.0) |
North-eastern | 2 (4.0) |
History of varicella infection | 9 (18.0) |
History of varicella vaccination | 7 (14.0) |
Comorbidities | |
Hepatitis B Infection | 4 (8.0) |
Malignancy* | 2 (4.0) |
SLE | 2 (4.0) |
HIV | 1 (2.0) |
*Oropharyngeal cancer and Hodgkin lymphoma
Nine patients (18%) had a history of previous varicella by history taking. The mean age (SD) of having the first episode was 8.7 (6.4) years. Seven patients (14%) had a history of varicella vaccination and six (85.7%) were healthcare professionals. All vaccinated patients received vaccines approximately 10 years or less prior to this infection. Immunosuppression was identified in six patients (10%) who had HIV infection, malignancy, systemic lupus erythematosus, currently taking an immunosuppressive drug, and kidney transplantation. All immunocompromised patients were unvaccinated. One patient was pregnant. Other patients with comorbidities are shown in Table 1.
All patients came to the hospital within the first seven days of onset. Almost half of the patients (48%) visited the OPD within 48 hours after noticing the initial lesions. Fever was reported in 38%. The clinical presentation on each visit date is shown in Fig. 1. Thirty-six percent of the patients presented with more than one type of lesion (multi-stage lesions). Almost all patients had vesicles (94%). Seventeen patients presented with papules (34%). Vesicles and papules were the main presentation during the first four days and began to decrease on day 5, however, they could be observed on any visit date. Scabs could be found on day 4 through day 7 and pustules were observed on day 6 and 7. Overall, 47 of 50 (94%) lesions were generalized (Table 2). Only two patients presented with lesions on the head, neck, and trunk without lesions on the extremities, and only one patient had lesions only on the truncal area. Neither patient presented with lesions only on the head and neck, nor the upper and lower extremities. Scabs and pustules were also present, but to a lesser extent, and were not found in patients with a history of varicella or VZV vaccination.
Table 2
Clinical features of 50 adult patients diagnosed with varicella visiting the dermatology clinic at Siriraj hospital, Jan 2018 - Jun 2022
Clinical features | N (%) |
Area of lesions | |
Generalized | 47 (94.0) |
Head, neck and trunk | 2 (4.0) |
Trunk only | 1 (2.0) |
Clinical presentation* | |
Vesicles | 47 (94.0) |
Papules | 17 (34.0) |
Scabs | 5 (10.0) |
Pustules | 2 (4.0) |
Complications** | 27 (54.0) |
Post-inflammatory hyperpigmentation | 27 (100.0) |
Secondary infection | 5 (18.5) |
Tzanck smear | |
Done | 46 (92.0) |
Positive | 42 (91.3) |
VZV Antigen | |
Done | 5 (10.0) |
Positive | 4 (8.0) |
Treatment | |
Oral Acyclovir | 47 (94.0) |
Oral Valacyclovir | 2 (4.0) |
Intravenous Acyclovir | 1 (2.0) |
Topical Antibiotics | 33 (66.0) |
Oral antibiotics | 2 (4.0) |
Antihistamine | 19 (38.0) |
Cure duration (days), median | |
Cases who came for follow up (N = 39) | 10 |
Cases started treatment within 48 hours of the first lesion (N = 20) | 9 |
Cases started treatment after 48 hours of the first lesion (N = 19) | 11 |
*May have more than 1 clinical presentation in 1 case
**May have more than 1 complication in 1 case
Wet dressing was recommended in all patients with varicella who had vesicles and pustules. Oral acyclovir or valacyclovir, respectively, was prescribed in 47 patients (94%) and 2 patients (4%), intravenous acyclovir was administered in one patient who received an immunosuppressive drug.
Thirty-nine patients (78%) completed the follow-up. At the first visit and during follow-up, about half of them reported having complications, most of which were mild. Twenty-seven patients (54%) reported hyperpigmentation after healing. Secondary bacterial infection was observed in 5 patients (10%). However, no serious complications including pneumonia, hepatitis encephalitis, or acute retinal necrosis syndrome were found. The median time to cure was 10 days, ranging from 4 to 18 days. The median cure duration of those who received varicella vaccination was eight days, while the median cure duration of those who did not receive vaccination was 11 days, as shown in Fig. 2a. The crude HR of those who had vaccination compared to those who did not was 4.20 (95% CI: 1.54, 11.49), and this was statistically significant with p = 0.005. Furthermore, it was observed that the cure duration of the vaccination group was shorter than that of the non-vaccination group by approximately three days (Table 3). Then further analysis was performed, patients were classified into two groups, those who received treatment within 48 hours after the onset of the rash (group 1), and those who received treatment after 48 hours after the onset (group 2). The median cure time of group 1 versus group 2 was 9 days versus 11 days, respectively (Fig. 2b) with a crude HR of 1.73 (95% CI 0.89, 3.35), the cure duration between the two groups did not show statistical significance (p = 0.11) (Table 3). The median duration of cure did not show statistical significance when classified by history of previous varicella (p = 0.15), age (p = 0.93), sex (p = 0.24), or immune status (p = 0.53). In the multivariate analysis, the adjusted HR of those with a history of vaccination was 5.50 (95% CI 1.58, 19.18, p = 0.007. The duration of cure was not significantly associated with age, sex, receiving treatment within 48 hours after the initial lesions or having a history of prior varicella.
Table 3
Crude and adjusted HR of factors related to duration of cure in 50 adult patients diagnosed with varicella visiting the dermatology clinic at Siriraj hospital, Jan 2018 - Jun 2022
Factors | Crude HR* (95% CI) | p-value | Adjusted HR** (95% CI) | p-value |
Sex | 1.53 (0.76, 3.07) | 0.24 | 1.67 (0.73, 3.81) | 0.22 |
Age (years) | 1.00 (0.97, 1.03) | 0.93 | 1.01 (0.98, 1.05) | 0.55 |
History of vaccination | 4.20 (1.54, 11.49) | 0.005 | 5.50 (1.58, 19.18) | 0.007 |
Onset ≤ 48 hrs | 1.73 (0.89, 3.35) | 0.11 | 1.01 (0.45, 2.27) | 0.99 |
History of previous varicella | 0.553 (0.24, 1.28) | 0.15 | - | - |
Immune status | 0.75 (0.31, 1.81) | 0.53 | - | - |
*Crude Hazard Ratio (HR) was analyzed using Cox’s proportional hazard model.
**Adjusted by sex, age, history of vaccination and onset ≤ 48 hrs.
July and May were the months of the highest and lowest average patients per month of 2 and 0.2 patients per month, respectively. The mean temperature from January 2018 to June 2022 was 29.1 degrees Celsius (Fig. 3). This was shown to be true as the average number of patients per month decreased sharply in months with temperatures of 30 degrees Celsius or higher. The months were then classified into two groups, 30 degrees Celsius or higher (group 1) and less than 30 degrees Celsius (group 2). The number of patients per month in group 1 versus group 2 was 0.40 versus 1.52 patients per month, respectively (p < 0.0001).