Viral Exanthems Overview

Study Notes

Definition and Types

Viral exanthems are skin rashes caused by viral infections.
They present as eruptions on the skin, often with fever and other systemic symptoms.
Different viral infections cause different patterns and characteristics of rashes.
Examples include measles, rubella, chickenpox, fifth disease, and roseola.

Measles (Rubeola)

Highly contagious airborne viral infection.
Characterized by a distinctive maculopapular rash that begins on the face and spreads to the rest of the body.
Often accompanied by fever, cough, runny nose, and conjunctivitis (inflammation of the conjunctiva).
Koplik's spots (small bluish-white spots on the buccal mucosa) are a characteristic early sign.
Significant morbidity and mortality, especially in malnourished children.

Rubella (German Measles)

More mild than measles.
Rash is often less prominent and may be maculopapular or macular.
Rash typically appears on the face and spreads to the neck, trunk, and extremities.
Often accompanied by mild fever and lymphadenopathy (swollen lymph nodes).
Congenital rubella syndrome (CRS) can occur if a pregnant woman contracts rubella, leading to significant birth defects in the fetus.

Chickenpox (Varicella)

Highly contagious viral infection.
Characterized by a vesicular rash.
Fluid-filled blisters (vesicles) appear on the skin, are itchy, and ultimately crust over.
Lesions are typically distributed over the whole body and develop in crops, progressing from macules to papules to vesicles.
Fever accompanies the rash.

Fifth Disease (Erythema Infectiosum)

Caused by parvovirus B19.
Known for the classic "slapped cheek" appearance, characterized by a bright red, flat rash on the cheeks.
Rash can spread to the extremities and trunk.
Often accompanied by mild fever and malaise.
Can cause anemia in susceptible individuals and a unique rash pattern in those with hemoglobinopathies.

Roseola Infantum

Primarily affects infants and young children.
Characterized by a sudden high fever, followed by a diffuse maculopapular rash.
Rash appears 3-5 days after the fever subsides, typically on the trunk and spreads to the extremities.
Often the only clinical manifestation of the disease.
Generally benign and resolves without treatment.

Diagnostic Considerations

Clinical presentation and history are important elements of the diagnosis.
Physical examination is crucial for recognizing characteristic rash patterns.
Laboratory tests like viral cultures or serologic assays can assist in confirming the diagnosis in specific cases.

Treatment and Prevention

Primarily supportive care, focusing on symptomatic relief, fluids, and fever reduction.
Antiviral medications may be given in specific cases, especially in immunocompromised individuals or for severe presentations, but are generally not indicated for most viral exanthems.
Vaccination is the most effective preventative measure for many viral exanthems.
Proper hygiene, particularly handwashing, is important in preventing the spread of viral infections.

Complications

Secondary bacterial skin infections can occur from scratching the rash.
Serious complications are rare, but can include pneumonia or encephalitis in cases of measles.
Congenital rubella syndrome can result in severe birth defects.

Description

This quiz covers the definition, types, and characteristics of viral exanthems, including notable infections like measles and rubella. You'll explore the symptoms, rash appearance, and complications associated with these viral infections. Test your knowledge on these common contagious diseases.