Viral Rashes: What You Need to Know

Written by Dr. Gabriela Maloney
Edited by Dr. Paul M. Graham  

Many viral illnesses are known to cause localized or generalized skin rashes known as viral exanthems. These skin rashes are a very common reason why patients and parents seek the care of a dermatologist. In this article, we will discuss various viral rashes, highlighting the important details of each.

Prompt recognition is important for appropriate care, guidance, and consideration of all at-risk individuals who have come in contact (i.e. pregnant females, infants, immunosuppressed, etc). Identification of the exact culprit virus might not always be possible, but a general knowledge of the most common etiologies is important.

Viral rashes can be classified as morbiliform (“measles-like”), rubelliform (“rubella-like”), scarlatiniform (“scarlet fever-like”), or urticarial (“hive-like”). The characteristics of the skin lesions, pattern of distribution, associated symptoms, and timeline of events are extremely important when gathering information to make a proper diagnosis. We will discuss a few classic skin exanthems below.

Hand-Foot-Mouth Disease

 Hand-foot-mouth disease is a common viral exanthem affecting children under 10 years of age. It is caused by multiple enteroviruses, most commonly coxsackievirus A16, that are transmitted via fecal-oral route and are most prevalent during the summer.

This disease initially presents with a fever, malaise and abdominal pain. These symptoms are then followed by the classic rash that gives the disease its name. Multiple gray-white blisters (vesicles) appear on the palms, soles, buttocks, and occasionally the face. Painful blisters can also occur in the mouth on the gums (gingiva), tongue, and palate, possibly leading to poor oral intake and dehydration. The disease is temporary and will resolve within a few days, but appropriate fluid intake must be maintained.

 “Slapped cheek” disease

Erythema infectiosum, also known as “slapped cheek” disease, is another common childhood viral rash. It is caused by parvovirus B19 and is transmitted via respiratory droplets (saliva). The disease affects school age children and initially presents with a fever, headache, and chills. During the second week of the illness, a bright red macular rash appears over the cheeks and is followed by the development of a lacy, reticulated rash on the chest, back, arms, and legs. The rash tends to fade over two to three weeks, but may recur with exposure to sunlight and warm temperatures (hot baths or exercise). Joint pains involving the hands, wrists, knees, and/or the ankles can occur in 8 to 10% of affected children and resolves over several weeks.

The parvovirus B19 binds to red blood cells and can result in a temporary anemia (low blood cell count), which could be problematic in patients with red blood cell disorders (sickle cell anemia, thalassemia, glucose-6-phosphate dehydrogenase deficiency, and private kinase deficiency). Adult infections are usually asymptomatic, but may cause joint pain in the small joints of the hands. Approximately 30 to 66% of adults develop antibodies against the virus. However, if a non-immune pregnant female contracts the virus during the first 20 weeks of pregnancy, fetal infection could occur.

Gianotti-Crosti Syndrome

Gianotti-Crosti Syndrome, also known as papular acrodermatitis of childhood, is a
symmetric rash consisting of red bumps on the face, buttocks, and extremities. It occurs in children between six months to six years of age and it can be secondary to several viral agents including Epstein-Bar virus (EBV), cytomegalovirus (CMV), coxsackievirus, RSV, rotavirus, and hepatitis B.
Affected children typically present with upper respiratory symptoms, fever, and lymph node enlargement prior to the onset of the rash. This is followed by the development of red bumps and blisters on the face, buttocks and extensor surfaces of the arms and legs. The chest and back are typically spared and the skin lesions are often asymptomatic. These skin lesions completely resolve over 8-12 weeks.

Roseola

Roseola infantum, also known as exanthem subitum, is a common disease caused by herpesvirus (HHV) type 6 or 7. This affects children between 6 months to 3 years of age. Viral transmission is primarily through saliva and symptoms initially present with a high fever (101-106^o F) lasting 3 to 5 days. The rash often appears after the fever subsides and consists of multiple pink-red colored spots and bumps on the chest and back, spreading to the arms, legs, neck, and face. The skin lesions may occasionally be surrounded by a white halo. Resolution typically occurs within 1 to 3 days after the rash develops. Associated symptoms can include irritability, diarrhea, cough, lymph node enlargement, and facial swelling. Red bumps can occur in the soft palate, which are known as Nagayama spots. Roseola is a common cause of febrile seizures in young children, but treatment is unnecessary as this condition usually resolves spontaneously without long term effects. 

Rubella (German Measles)

Rubella, also known as german measles, is an uncommon disease caused by a togavirus. Since the initiation of the childhood vaccination program, the incidence has markedly decreased, but outbreaks may still occur. Rubella is typically spread by direct contact or through respiratory droplets (saliva). Symptoms are typically minimal or completely absent, including fever, headache, fatigue, sore throat, runny nose, and muscle aches. Lymph node enlargement is common, especially on the head and neck.

Approximately 2-3 weeks after the initial infection, the rash develops. The skin rash consist of red-pink colored spots and bumps initially involving the face, and rapidly spreading to the chest, back, arms, and legs. The rash typically resolves after 1-3 days. Treatment is often not required, but may be initiated in newborns affected prior to delivery.

Rubeola (Measles)

Rubeola, also known as measles, is another uncommon disease of childhood and is caused by a paramyxovirus. As with rubella, the incidence has largely decreased after the introduction of the childhood vaccination program. The virus is contracted through respiratory droplets (saliva), initially infecting the inner nose and spreading to lymph nodes and the blood stream. The virus undergoes rapid spread throughout the body, stimulating the immune system to develop protective antibodies. Initial symptoms of measles can be remembered by the three Cs: cough, conjunctivitis, and coryza (runny nose). Gray-white spots may appear on the roof of the mouth, known as Koplik spots. These typically develop prior to the rash, but are not always present.

The skin rash begins 2-4 days after the above symptoms develop. It often appears as red patches starting on the face and rapidly spreading to the chest, back, arms, and legs. Treatment is often not required but may be recommended. Vitamin A supplementation can be used in severe cases as it has been shown to reduce mortality and decrease the severity of the symptoms.

Photo Credit: Thesilverink.com, BBC.com, Dermquest.com, Newkidscenter.com, Walesfirst.org, Pbs.twimg.com

References

1. Clinical Pediatric Dermatology. Fifth edition. 2011:382-99.
2. Dermatology. Third edition. 2012:1345-54.
3. Dyer, J. Childhood viral exanthems. Ped Annals. 2007;36:21-9.

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