Viral Skin Rashes and Diseases

Smallpox

• Caused by the Variola virus
• Belongs to the family of viruses known as the Poxviruses
• One of the largest and most complex animal viruses
• Enveloped with a brick-shaped appearance
• Unique DNA viruses
• Multiply in the cytoplasm of host cells called factory areas
• Produce eruptive skin pustules called pocks or pox, which leave small, depressed scars (pockmarks) upon healing
• A strictly human pathogen
• Spread through respiratory droplets and fomites
• Enters the body via the nasopharynx
• Fever ensues
• Travels throughout the body in the blood
• Vesicular rash develops throughout the body
• Death was usually a result of complications from pneumonia, heart failure, and a severe immune response to the virus
• Millions of people worldwide died from smallpox infections annually
• Eradicated in the 1970s
• A major success by the World Health Organization (WHO)
• Concern exists about the risk of reemergence because of stockpiles of the virus still stored in government labs
• The general population is no longer vaccinated
• Certain members of the military and high-ranking politicians have opted to receive the smallpox vaccine
• The monkeypox virus is closely related to the variola virus
• People vaccinated against variola were also immune to monkeypox, keeping monkeypox infection rates low
• With the decline in variola vaccinations, monkeypox infection rates are increasing

Chickenpox and Shingles

• Caused by the Varicella-Zoster Virus (VZV), an enveloped DNA virus
• Also known as human herpesvirus-3 (HHV-3)
• Belongs to the Herpesvirus family (includes HSV-1 and HSV-2)
• Extremely communicable
• Transmitted mainly via respiratory droplets or by fluid from skin lesions
• Replicates in the respiratory mucosa (incubation period of 10-20 days)
• Travels through the bloodstream and spreads throughout the body
• The initial infection with VZV causes Chickenpox (Varicella)
• Chickenpox manifests as a fever and itchy, vesicular rash on the trunk, face, scalp, and extremities
• Infection typically resolves on its own within a few weeks
• More serious diseases including pneumonia can occur, especially in the immunocompromised population
• The incidence of chickenpox has dramatically decreased since a vaccine is now widely used
• VZV can cause a secondary infection known as Shingles (Zoster)
• In people who have contracted chickenpox, the virus goes latent in the neurons (more specifically the dorsal root ganglia)
• The virus can be reactivated later, leading to shingles
• Shingles is a very painful and tender vesicular rash that typically forms on one side of the face or body along the the pathway of the nerves in which the virus went latent
• Anyone who has had chickenpox is at risk of developing shingles
• Those at highest risk are the immunocompromised or people aged 60 or older
• A shingles vaccine is FDA-approved for patients 60 years of age or older
• Patients with shingles can cause chickenpox in individuals who are unvaccinated and susceptible to the infection

Measles

• One of the most contagious infectious diseases
• Spread via respiratory droplets
• An enveloped, RNA virus only found in humans
• People who contract measles develop a fever, sore throat, red eyes, runny nose, followed by a dark red, blotchy rash all over the body
• Vaccination with the MMR (measles, mumps, and rubella) vaccine provides immunity to measles
• Measles cases dramatically declined as a result of vaccination
• Vaccination is recommended because of possible complications, including death due to brain damage
• Vaccination rates have been declining in certain U.S. populations, notably in California
• These susceptible populations are vulnerable to outbreaks
• Eradicated in the U.S., meaning that regular transmission within the U.S. population is no longer expected
• Prevalent in other parts of the world
• Easily brought to the U.S. by international travelers
• A distinguishing feature of measles is the presence of Koplik's spots, small white spots on the inside of the patients cheek

Rubella

• A contagious rash accompanied by a fever
• Caused by the Rubella virus, an enveloped, RNA virus
• Sometimes called "German measles" or "three day measles"
• Typically not severe in children and adults
• About half of the individuals that contract rubella experience no symptoms
• Can lead to very serious birth defects for the developing fetus if a pregnant woman contracts the virus
• Causes deafness, heart defects, and mental retardation in newborns
• A vaccine is available to protect against this disease and is included in the MMR vaccine
• Has a similar appearance to measles, but the rash is usually less intensely red than the measles rash

Warts

• Also called papillomas
• Benign, squamous epithelial growths
• Caused by the Human Papilloma Viruses (HPV)
• Naked, DNA viruses with a circular strand of DNA
• Different strains of HPV infect different tissues and can cause different kinds of warts
• Plantar warts (deep painful warts on the soles of the feet)
• Common seed warts (smooth, skin-colored warts anywhere on the skin)
• Genital warts (form on the mucous membranes of the genital region)
• Most warts are harmless and will self-resolve without treatment
• Genital warts dramatically increase the risk of various cancers
• HPV viruses are transmitted between humans through direct contact
• Often spread from one part of the body to another through autoinoculation
• There is evidence to show that the virus can be transmitted via towels and other fomites

Molluscum contagiosum

• An infection that can look similar to warts
• Caused by the molluscum contagiosum viruses
• Belong to the Poxvirus family
• Form smooth, waxy nodules on the face, trunk and limbs that may have a milky looking fluid inside them
• Papules can form anywhere on the body
• Common in children
• In adults, it most commonly presents around the genitals
• Transmitted through direct contact, sexual contact, and autoinoculation

Smallpox

• Caused by the Variola virus, a member of the Poxvirus family
• Large, brick-shaped virus with a complex capsid and envelope
• Spreads through respiratory droplets and fomites
• Enters the body through the nasopharynx
• Causes fever, a vesicular rash, and can lead to pneumonia, heart failure, and a severe immune response
• Eradicated in the 1970s due to vaccination and isolation programs
• A potential bioterrorism agent due to stockpiles in government labs
• The general population is no longer vaccinated against smallpox

Chickenpox and Shingles

• Caused by the Varicella-Zoster Virus (VZV), a member of the Herpesvirus family
• Highly contagious and spread through respiratory droplets and fluid from skin lesions
• Initial infection causes Chickenpox (Varicella), characterized by fever and an itchy, vesicular rash
• Can cause a secondary infection known as Shingles (Zoster)
• VZV goes latent in neurons after chickenpox and can be reactivated, leading to shingles
• Shingles is a painful, vesicular rash that typically forms on one side of the face or body
• A shingles vaccine is available for patients 60 years or older

Measles

• One of the most contagious infectious diseases, spread through respiratory droplets
• An enveloped, RNA virus found only in humans
• Causes fever, sore throat, red eyes, runny nose, and a dark red, blotchy rash
• Vaccination with the MMR (measles, mumps, and rubella) vaccine provides immunity
• Eradicated in the U.S. but still prevalent in other parts of the world
• A distinguishing feature of measles is the presence of Koplik's spots, small white spots on the inside of the cheek

Rubella

• A contagious rash accompanied by fever, caused by the Rubella virus, an enveloped, RNA virus
• Also known as "German measles" or "three-day measles"
• Typically not severe in children and adults, with half of individuals experiencing no symptoms
• Can lead to serious birth defects if contracted by a pregnant woman
• Causes deafness, heart defects, and mental retardation in newborns
• A vaccine is available to protect against rubella and is included in the MMR vaccine
• The rash is less intensely red than the measles rash

Warts

• Benign, squamous epithelial growths caused by Human Papilloma Viruses (HPV)
• Naked, DNA viruses with a circular strand of DNA
• Different strains infect different tissues and cause different types of warts: plantar warts, common seed warts, and genital warts
• Most warts are harmless and self-resolve, except for genital warts, which increase the risk of various cancers
• Transmitted through direct contact and autoinoculation
• Can be transmitted via towels and other fomites

Molluscum Contagiosum

• Caused by the Molluscum Contagiosum virus, a member of the Poxvirus family
• Forms smooth, waxy nodules on the face, trunk, and limbs
• Transmitted through direct contact, sexual contact, and autoinoculation
• Common in children but can present around the genitals in adults