Viral exanthems refers to a widespread rash and eruptions that accompany a viral infection and its symptoms of fever, fatigue, and body ache.
There are many different kinds of viruses that can cause exanthems.
The common viral exanthems of childhood are chickenpox, measles (rubeola), German measles (rubella), and hand-foot and mouth disease (tomato fever). Other exanthems include fifth (erythema infectiosum) and sixth (roseola infantum) disease.
Mumps and infectious mononucleosis (mono) can also present with rash, and are sometimes referred to as viral exanthems.
These viruses are contagious and can spread by close contact through respiratory droplets (shed by coughing/sneezing) and by direct contact with skin eruptions and recently contaminated objects. While most viral exanthems are common in children <5 years, some of them can also affect older children, teens, and adults especially those who have not acquired immunity to these viruses by either childhood infection or vaccination.
Viral exanthems are caused by different groups of viruses like herpesvirus (varicella zoster – chickenpox, Epstein–Barr – Infectious mononucleosis, herpesvirus 6/7- sixth disease), paramyxovirus (mumps, measles), togavirus (rubella), picornavirus (hand-foot-mouth disease), and parvovirus (fifth disease).
Viral exanthems can also occur due to ‘pox’ which is also a viral disease characterized by rash and eruptions of the skin and/or mouth. Pox virus (orthopoxvirus) is a group that includes viruses causing smallpox in humans, and related animal pox like cowpox, monkeypox, camelpox, horsepox, raccoon pox, and many others. Smallpox has been eradicated with effective mass vaccination, almost 5 decades back. However, pox diseases from animals are occasionally contracted by humans in close contact with animals, thereafter causing its local spread in human community pockets, some particular regions, or rarely across countries (as seen recently with monkeypox). Any age group can be affected when such animal pox spreads in humans.
Chickenpox resembled smallpox in appearance, so it got the suffix ‘pox’ though it is not caused by the pox virus and is far less severe and serious.
SIGNS AND SYMPTOMS
The preceding and accompanying symptoms can include fever, malaise, fatigue, body pain, muscle pain, headache, and sometimes sore throat, and general flu-like symptoms.
The rash appears around 1-5 days after fever, and starts as red patches (macules), then progresses to raised bumps or eruptions (papules) that start to blister by filling with a whitish fluid. After a few days, these blisters dry and form scabs or crusts that heal and fall off. The eruptions can be quite itchy but usually not painful. Itching and break-down (ulceration) of the blisters can sometimes leave scars after the scabs fall off, but most of these lighten and go away with time.
The rash appears first on the trunk (chest/back), and then on the face and entire body, usually sparing the palms and soles. It usually lasts for up to a week. The eruptions in chicken pox develop rapidly, are very itchy, and are in different stages of development, so look variable.
Fever, headache, and body ache may precede the rash, but flu-like symptoms are rare.
Shingles (Herpes zoster) is seen in adults who have had chickenpox in childhood and the virus that remained dormant for many years, has been reactivated due to a drop in immunity resulting from age, stress, and other illnesses. Unlike chickenpox, shingles cause a painful rash that may appear as a line of blisters on the trunk or face. Pain can persist even after the rash is gone (post-herpetic neuralgia).
The rash and eruptions first appear on the forehead and then spread to the entire body including hands and feet. The eruptions are diffuse, flatter, and less itchy compared to chicken pox, lasting up to 2 weeks.
Preceding flu-like symptoms of sore throat, runny nose, and cough are more common in measles, and occasionally lymphadenopathy (swollen lymph nodes) can be present.
The rash is similar to measles, but fever and flu-like symptoms are rare. It is milder and much shorter in duration than measles but can cause complications in pregnant women like miscarriage and birth defects.
Also sometimes called ‘tomato fever’, this is a condition seen in young children causing sores in the mouth and a rash on the hands and feet.
Children have fever, sore throat, loss of appetite, and feel unwell and irritable. Lymph nodes in the neck may also become swollen.
The mouth sores are painful and develop within 1-2 days of the fever, followed by the rash that looks like tomatoes, and is prominent on hands and feet giving the disease its name. It can also occur on buttocks and genitals, and sometimes other parts of the body. The eruptions usually are not that itchy, and do not leave scars.
It is self-limiting and usually resolves in a week to 10 days with supportive care.
Fifth and Sixth Disease
Fifth disease (erythema infectiosum) causes a distinctive itchy facial rash called ‘slapped cheek’ appearance (not seen in every case). There may also be a lacy red rash on the trunk and limbs. Sore throat, mild fever, indigestion, headache, and fatigue are other symptoms. The virus usually clears up on its own. It usually affects young children, but rarely adults may be affected. Some cases may show joint pain and swelling (seen more in adults).
Sixth disease (roseola infantum) is seen mainly in children <2 years and rarely adults. It can cause high fever and cold symptoms. The rash appears as many small, pink spots, that begin on the trunk and may spread to the neck and limbs. It is also self-limiting with supportive treatment.
A rash may sometimes accompany some not all cases of mumps. It usually starts on the face and spreads all over the body. The hallmark and differentiating feature of mumps is the painful swelling of the salivary glands located in the cheek-jaw area.
This is a condition with fever, fatigue, body ache, and swollen lymph nodes, and may be accompanied by a rash in some cases. It affects teenagers and young adults more commonly, and unlike the other exanthems mentioned, this condition is more common in developed countries. It is also called mono and ‘kissing disease’ due to its direct spread by saliva. It is self-limiting in 2-3 weeks, though fatigue can last up to a few months.
When it occurs in humans it can sometimes be confused with chickenpox or measles, especially in populations not vaccinated or immune to the latter. Monkeypox rash begins on the face and then spreads to other parts of the body including palms and soles. It can last up to 3 weeks. The eruptions are sharply raised, firm, and round with a dot on top (called umbilication). The eruptions in monkeypox develop slowly and look alike and uniform in the same stage of development.
The rash is preceded by fever, bodyache and fatigue. There is usually lymphadenopathy (swollen lymph nodes) and flu-like symptoms in monkeypox that are not commonly seen with chickenpox.
All the above viral exanthems are self-limiting and run their course. Treatment is only supportive. Complications are rare but can include diarrhea and sometimes effects on organs like the heart (pericarditis, myocarditis), lungs (pneumonia), pancreas (pancreatitis), testes and ovaries (orchitis and oophoritis respectively – seen in mumps), brain (encephalitis), or ear (otitis, decreased hearing). One should be alert for evidence of complications in very young children, and in adults.
In most countries, vaccination is now available and part of the childhood immunization schedule for measles, mumps, rubella, and chickenpox. These viral exanthems are therefore rare in current times. Shingles vaccine is also available for those 50 years and above.
The diagnosis is usually clinical, based on the symptoms, characteristics, and onset of the rash and eruptions, age of the patient, as well as the epidemiology of prevalence and spread of viral infections in that particular area.
However, lab diagnostic tests are available. A swab taken from the eruptions is subjected to polymerase chain reaction (PCR) tests for antigen detection. Serological testing (blood test to check for specific antibodies to the suspected virus) is also available. Swab tests and serology is done is not done routinely, unless the spread of a particular disease is being monitored and analyzed, as currently for hand-foot-mouth disease in India, and now monkeypox globally.
All these conditions resolve on their own after running their course. Treatment is non-specific and supportive. Rest, a healthy nutritious diet, and plenty of water and fluids like herbal tea, buttermilk, and coconut water to maintain hydration, are the three cornerstones of treatment.
To soothe the itching, the doctor may prescribe calamine lotion. In severe itching, an oral antihistamine or a cream with a mild-moderate corticosteroid may be given. Other soothing agents include neem leaves, aloe vera, natural oils like coconut, lavender, or tea tree oil, honey, chamomile compresses, and oatmeal preparations. Cool baths with baking soda added, or applying a cool, wet cloth on the skin for 15 to 30 minutes several times a day, can also help soothe irritation and relieve itching.
Antiviral medicines are given in very rare and severe cases under the doctor’s advice and are not usually needed. Antibiotics are not to be given except when there is a secondary bacterial infection diagnosed by the doctor.
Red Flag Signs
One should be aware of alert signs for complications, especially in very young children, and older adults. In case any of the signs below occur, one should take consult a doctor immediately:
- Severe headache, stiff neck, confusion, unconsciousness, or seizures
- Severe cough, chest pain, or breathlessness
- Severe abdominal pain
- High fever for more than a day
- Diarrhea or vomiting
- Dizziness or fainting
- Red eyes, mouth, or tongue
- Swollen, painful joints
- Decreased hearing or ear pain
- It is important to vaccinate all children by 2 years for chicken pox, measles, mumps, and rubella.
- If any viral exanthem is spreading in your area then take care of cleanliness and hygiene, and stay away from anyone who is unwell.
- Avoid touching your eyes, nose, and mouth.
- Wash and sanitize your hands often, especially just before you eat.
- Wash in hot water and handle with gloves, all linen used by someone who is unwell in the house.
- Clean commonly used surfaces, like doorknobs and countertops, before and after you handle them.