What type of skin rash was more prevalent in the United States (US) prior to 1990?

From the Guidelines

Varicella rash was more prevalent in the United States prior to 1990. The varicella rash, also known as chickenpox, typically appears as a blister-like rash, starting on the trunk and spreading to other parts of the body. This rash was more prevalent before 1990 due to the fact that varicella was a universal childhood disease in the United States, with an average annual incidence of 15--16 cases per 1,000 population 1. According to the data from the National Health Interview Survey (NHIS) for 1980--1990, an average of 4 million cases were estimated to have occurred annually 1. The epidemiology of varicella is characterized by its high contagiousness, with 80% to 90% of susceptible people exposed in a household setting developing clinical infection 1. Transmission occurs via direct contact, airborne droplets, or infected respiratory tract secretions, and the virus initially enters a susceptible host through the upper respiratory tract or the conjunctivae 1. The introduction of varicella vaccine in 1995 significantly reduced the incidence of varicella and associated rashes, making varicella a less common disease in the United States. Key characteristics of varicella include:

• High contagiousness, with 80% to 90% of susceptible people exposed in a household setting developing clinical infection 1
• Transmission via direct contact, airborne droplets, or infected respiratory tract secretions 1
• Average annual incidence of 15--16 cases per 1,000 population before the introduction of varicella vaccine in 1995 1
• An average of 4 million cases estimated to have occurred annually in the United States before 1990 1

From the Research

Prevalence of Skin Rashes in the US Prior to 1990

• Varicella-zoster virus (VZV) was a common cause of skin rashes in the US prior to 1990, with varicella (chickenpox) being a ubiquitous human alphaherpesvirus that causes a highly infectious disease, especially prevalent in children 2.
• Chickenpox was characterized by fever, viremia, and scattered vesicular lesions of the skin, and was often mild in children, but the severity of the disease increased with age 3, 4.
• Herpes zoster (shingles), caused by VZV reactivation, was a localized, painful, vesicular rash involving one or adjacent dermatomes, and its incidence increased with age or immunosuppression 3, 2, 5.
• There is no direct evidence to suggest that other skin rashes, such as monkeypox or smallpox, were more prevalent in the US prior to 1990, as variola virus (the cause of smallpox) was eradicated in the 1980s 6.

Characteristics of Varicella-Zoster Virus Infection

• VZV established latency in cells of the dorsal root ganglia, and reactivation of the virus could lead to herpes zoster (shingles) 2, 5.
• The virus was found in a worldwide geographic distribution, but was more prevalent in temperate climates 2.
• Primary VZV infection elicited immunoglobulin G (IgG), IgM, and IgA antibodies, which bound to many classes of viral proteins, and virus-specific cellular immunity was critical for controlling viral replication in healthy and immunocompromised patients 2.