Viral Exanthem Rash - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Exanthem is a widespread rash in the body, often accompanied by systemic symptoms like malaise, headache, and fever. It can occur due to a viral infection, a reaction to a toxin, a skin reaction to microbial infection, or a result of an immune reaction. Viral exanthem rash is bumps, spots, or patches on the skin that occur during a viral infection. It can appear on any part of the body, such as the face or trunk, and then spread to the rest of the body.

What Is Viral Exanthem Rash?

Exanthem is the medical term for rash due to a systemic condition; a rash associated with a viral infection is called viral exanthem rash.

What Are the Causes of Viral Exanthem Rash?

The most common cause of a viral exanthem is a viral infection, such as

• Measles (morbillivirus).

• Chickenpox (varicella).

• Rubella (rubella virus).

• Erythema infectiosum (parvovirus B19).

• Roseola (herpes virus 6B).

Viral exanthems can also be caused by systemic viral infections such as:

• Smallpox

• Viral hepatitis.

• Acute human immunodeficiency virus.

• Infectious mononucleosis.

• Pityriasis rosea (herpesvirus 6 and 7).

• Papular purpuric glove and socks syndrome.

• Nonspecific viral exanthem.

What Are the Symptoms of Viral Exanthems?

• A widespread rash, which is pink to red in color, is mainly seen on the arms, legs, and trunk.

• It may or may not cause an itch.

• Often accompanied by fever, headache, malaise or tiredness, aches and pains, loss of appetite, and irritability.

• The rash is more extensive on the trunk when compared to the extremities. Before a rash appears, the patient first experiences general unwellness.

• The symptoms vary depending on the cause of the rash. It can also be due to small epidemics, causing many to have similar symptoms at the same time.

What Are the Common Viral Exanthems?

In Children:

Roseola Infantum:

• Causative virus: Human herpesvirus 6 or 7 (HHV6 or HHV7)

• Spread respiratory droplets.

• Roseola mainly affects children aged between six months and two years.

• Symptoms include high fever, seizures due to fever (febrile seizures), upper respiratory tract symptoms, and lymphadenopathy. The fever lasts for three to five days.

• Once the fever subsides, the rash appears, and pink macules and papules appear on the trunk, which spreads to the extremities, neck, and even faces. Macules are flat, discolored areas of skin, whereas papules are raised areas in the skin. The rash fades after a few days.

• Roseola can be differentiated from measles; the maculopapular rash starts on the face and spreads to the limbs and trunk in measles.

Laterothoracic Exanthem:

• Laterothoracic exanthem is an uncommon disease found mostly in females of Caucasian ethnicity from age one to five.

• Causative virus: Epstein-Barr virus, parvovirus, and adenovirus.

• Exanthems start around the groin or axilla unilaterally and then spread centrifugally and become bilaterally.

• The characteristic symptom includes a tiny papule that is surrounded by a pale area, which gets flattened and scaly. It can be mistaken for eczema because of its appearance. It may be associated with gastrointestinal and respiratory symptoms. The older plaques can form a dusky gray discoloration.

• The rash resolves spontaneously within five weeks.

Hand, Foot, and Mouth Disease:

• Causative virus: Enterovirus, Coxsackie A16, and enterovirus 17.

• It spreads through fecal-oral routes.

• Symptoms include fever, sore mouth, and malaise. Mouth lesions appear before body rashes. Painful ulcerative lesions appear in the mouth.

• The exanthem appears as red macules, which have a red halo and form gray elliptical vesicles. It is seen in the hands, buttocks, and soles of feet. The vesicles gradually disappear in seven to ten days.

• Diagnosis can be confirmed by examining samples from the oropharynx, stool, blood, or skin vesicles.

• After the initial clinical presentations, nail changes can be observed in hand, foot, and mouth diseases such as Beau’s lines and onychomadesis.

Erythema Infectiosum:

• Slapped cheek disease or erythema infectiosum is caused by parvovirus, which spreads via respiratory droplets. It is commonly seen in children between the ages of four and ten.

• Rash follows a period of illness and develops in three stages:

  • First Stage: Consists of bright red cheeks without involving nasal ridge and area around the mouth.

  • Second Stage: About one to four days after the redness in the face, erythema appears on the extremities.

  • Third Stage: Occurs after the eruption fades and reappears when exposed to the sun or body temperature increases during exercises.

• Confirmatory diagnosis can be made by serological tests for anti-B19 infection.

• Parvovirus infection can cause thalassemia, hemolytic anemia, immunosuppression, and sickle cell disease. If pregnant women are affected, it can lead to hydrops fetalis.

Gianotti-Crosti syndrome:

• Papular acrodermatitis or Gianotti-Crosti syndrome is associated with EBV, coxsackievirus, cytomegalovirus, hepatitis A, B, and C, respiratory syncytial virus, parvovirus B19, HHV-6, echovirus, rotavirus, mumps, parainfluenza, and human immunodeficiency virus (HIV).

• It affects children between the ages between one and six; it is also seen in adults.

• Patients have a fever and upper respiratory tract symptoms that are followed by papules and papulovesicular eruption. It is found in the extensor surface of limbs, faces, and buttocks. It is usually not found in the trunk.

• The disease is self-limiting and resolves within eight weeks.

In Any Age:

Varicella:

• Varicella zoster virus is one of the human herpes viruses; it is known to cause two forms of diseases, chickenpox (varicella) and shingles (herpes zoster).

• The primary varicella-zoster infection causes chicken pox, which is spread via respiratory droplets.

• Rash has a characteristic feature which is a vesicular eruption that is seen on limbs, face, and trunk. The papule begins as two to four mm red lesions, which become vesicles and subsequently form crusts. The lesions heal within one to four weeks.

• The lesions are accompanied by fever, malaise, and fatigue.

• The disease has a more severe impact on the adult population and immunocompromised individuals. They tend to develop encephalitis, pneumonia, and hepatitis.

• Diagnosis is made by swab testing.

Measles:

• Measles is a highly contagious viral disease that spreads via respiratory droplets.

• Fever, cough, and conjunctivitis usually precede this disorder. Mouth lesions which are gray-white papules, develop on the buccal mucosa (inside of cheeks) before skin rashes develop. These are called Koplik spots and are indicative of measles.

• The rashes begin as red macules and papules on the head and spread downwards. By the fifth day, the rashes start fading.

• Serology tests, PCR tests, and swab tests can be done to confirm the diagnosis.

Rubella:

• Rubella is milder in clinical presentation than measles. Pink rashes begin on the face and spread to the trunk and extremities within 24 hours.

• Mouth lesions on the soft palate are found called Forchheimer spots.

• The rashes fade in two to three days.

• If it occurs during pregnancy, it can affect the fetus and is called congenital rubella syndrome.

• Arthritis is common in adults.

• Confirmation is by serology tests.

Viral Exanthems in Adults:

Pityriasis Rosea:

• Human herpes viruses, HHV-6 and HHV-7, are associated with this self-limiting condition.

• Well-demarcated scaly plaque is found on the trunks and limbs initially.

• It is then followed by a secondary eruption.

• The rash subsides in 12 weeks but can persist for more than five months.

• A biopsy is done for a confirmatory diagnosis.

Shingles:

• After a primary varicella infection, the latent neurons on the dorsal root ganglia can be reactivated by a trigger which can be old age, emotional stress, radiation therapy, or physical trauma; this can lead to shingles.

• It presents as burning pain, which is followed by eruptions. There may be associated malaise, fever, and lymphadenopathy.

• Lesions are present in the lower back and knee.

Papular purpuric Gloves and Sock Syndrome:

• Parvovirus B19 can cause a viral exanthem other than erythema infectiosum.

• It is common in young adults.

• There is redness, edema, purpura, and petechiae. Oral lesions can be seen in the hard and soft palate and tongue.

• It resolves in two weeks, and during the appearance of eruptions, the patients are infectious.

How to Diagnose Exanthems?

• Clinical presentation of different exanthems and the associated prodromal symptoms are typical of a disorder, which helps the clinician to differentiate the systemic cause.

• Laboratory tests can be done to confirm the disease, such as

  • Polymerase chain reaction (PCR), viral culture, and immunofluorescence.

  • Blood tests.

  • Genotyping.

How to Treat Exanthems?

• Since viral disorders do not have medication, the treatment is mainly symptomatic. Most exanthems are self-limiting.

• NSAIDs can be used to reduce fever.

• Moisturizer can be used to reduce the itch.

Conclusion:

Viral exanthems are rashes caused by a viral infection. Each viral infection has a characteristic pattern for rashes and associated symptoms before the rash appears clinically. This is helpful in identifying the underlying cause. Fever is treated with NSAIDs, and moisturizer can be used to reduce the itch. Most lesions are self-limiting and can be prevented by vaccinations.