Common Exanthematous Diseases of Childhood (Rashes of Childhood)

Exanthematous Diseases of ChildhoodExanthematous Diseases of Childhood


Exanthematous diseases are common conditions presenting during childhood. The clinical manifestations could be classified according to the skin lesions they produce during the course of the illness.

The most common causes of exanthematous diseases are viral infections, although bacterial infections and autoimmune conditions can also present with exanthemata.

Clinical history and pattern of presentation are useful for the differential diagnosis of exanthematous disease. Diagnostic testing includes serological studies, imaging, and autoimmune profile in selected cases.

Common Exanthematous Diseases of Childhood – Introduction

Often referred to as exanthematous rashes, or exanthematous disease, these manifestations are extremely common in children and commonly encountered by pediatricians, family doctors, and general practitioners in the hospital and the office.

It is most often associated with an infectious origin, usually viral, but it can also be produced by bacteria, generally associated with fever. Diagnosis is usually based on clinical presentation, prodrome, characteristics of rash, accompanying signs and symptoms, and microbiological studies.

In several decades, we have seen a shift in the epidemiology of many of these diseases; for example, measles has experienced a resurgence secondary to falling vaccination rates, and a new variant of hand, foot, and mouth disease has been associated with more widespread and atypical disease. Fortunately, almost all of them are self-limited, and the treatment can be followed as an outpatient, thanks to the introduction of routine vaccination. (1)

This article explains the different types of rashes and what causes them while summarizing the different aspects that should be considered for the diagnosis and management of the patients. A complete description of each disease, with the corresponding treatment, prognosis, and prevention, will be reviewed in future articles.

Definition of Exanthematous Disease

Exanthematous diseases include a spectrum of disorders caused by a variety of pathogens, usually self-limited, that affect children all over the world.

Exanthemas are generalized, erythematous rashes with an underlying cause; they are usually originated from a viral or bacterial infection, but there are also other possible causes, such as autoimmune disorders, drug reactions, genetic disorders, or physical injuries. When assessing patients presenting with rashes, the practitioner should consider the latter causes in the differentials. This is why it is important to learn to recognize them to provide the best treatment and care possible.

In this modern era, the more severe complications have lost a lot of prevalence due to the introduction of vaccines, although we still frequently see minor expressions of these illnesses in common practice.

Classification of Skin Lesions in Exanthematous Disease (5, 6, 7)

As we previously mentioned, various infectious and noninfectious agents can cause a cutaneous eruption and similar clinical symptoms. At the beginning of the consultation, we should pay special attention to the characteristics of the rash (shape, color, distribution, progression, evolution) since different viral and bacterial agents can cause similar manifestations on the skin.

Dermal manifestations and rashes can be categorized based on the form of the rash:

Macule-papule: Formed by two different types of lesions, where the macule is a circumscribed area of the skin where the color changes that reverse without leaving a scar and no elevation or depression of the skin, often associated with pruritus.

Papules are solid raised lesions up to 1 cm in greatest diameter. Most commonly seen in viral illnesses. This category also divides into two forms of expression:

  • Morbiliform: refers to the type of papules that spare healthy skin in between the compromised one. Examples of diseases that produce this type of rash are measles, rubella, infectious erythema, sudden erythema, hepatitis b, and other bacterial and viral infections, as well as drug reactions.
  • Scarlatiniform: In this case, the whole skin is compromised with the exanthema. Examples of diseases that produce this type of rash are scarlet fever, toxic shock syndrome, Kawasaki disease, and syphilis, among others.

Vesicular-bullous: Circumscribed, elevated, liquid-containing lesions that are considered vesicles when they are less than 0.5 mm in diameter and a bulla when greater than that. Examples of diseases that produce this type of rash are Varicella (chicken pox), porphyria, diabetes, and scalded skin syndrome, among others.

Petechial/Purpuric: Petechiae are pinpoint-sized spots of bleeding under the skin or mucus membranes. These are not itchy or elevated and are not considered a rash because they are produced by the rupture of tiny blood vessels and are non-blanching when tested. Color may vary from purple to brownish-red. Examples of diseases that produce this type of lesion are Malaria, Dengue fever, and Meningococcemia. Purpuric lesions refer to the same mechanism and greater diameter.

Nodular: Similar to a papule but is located in the hypodermis. Examples of diseases that produce this type of rash are Hepatitis C and erythema nodosum.

Epidemiology of Exanthematous Disease (2, 5)

Among the causes of exanthema, viral infections are by far the most common cause of fever with rash in children. Rubella or measles is a major public health problem with significant mortality and morbidity, especially in developing countries.

Another cause of rash could be bacterial, being the group A streptococcus (Streptococcus pyogenes), the most common cause of scarlet fever due to the release of endotoxins that cause a local inflammatory reaction in the skin producing the classic “sandpaper rash” (6). This type of bacteria is also associated with other skin diseases such as impetigo, erysipelas, cellulitis, and necrotizing fasciitis. Also, in a smaller amount, we can name other pathogens that can cause exanthema in children, like fungi, parasites, drugs, and autoimmune diseases.

The epidemiological characteristics that require special attention are:

Age of the patient: Considering age may assist in the diagnosis of the disease because the clinical manifestations may vary depending on the patient’s age.

Season of the year: Some pathogens are more prevalent at different times of the year. For example, measles and rubella are more common in the spring.

Geographic area: Some pathogens are more predisposed to survive, live and reproduce in different geographic regions.

Incubation period: The period between the exposure to the exanthematous infection and the appearance of the clinical symptoms may help the physician to identify the probable etiology.

Exposure history: We have to take into consideration the contact with animals, food, plants, and other patients with similar symptoms.

Drug history: Various drugs can cause exanthematic reactions.

History of Vaccination and Immunization: The knowledge of prior infection and history of vaccination can help us rule out some differential diagnoses. Considering the interval between the vaccine administration and the manifestation of the rash may help narrow down the cause.

History of sexual activity: Every patient with a rash should be interrogated about their sexual activity and examined accordingly. Human herpes and syphilis are diseases that can be linked to local and systemic rashes.

Etiology of Exanthematous Diseases

In this section, we will focus on what we think are the more important and useful etiology exanthemas to know:

Varicella: most commonly known as chicken pox, is caused by the Varicella-Zoster virus, an alpha herpesvirus that can cause Varicella (the primary infection) and Herpes Zoster (reactivation of the latent virus that remains in the ganglia). (8)

Rubella: Also known as “German measles” or “third disease.” Rubella virus belongs to the Togaviridae family and is the sole member of the Rubiviridae genus. Identifying this virus is important because it can spread to the placenta and cause congenital malformations in the fetus. (9)

Measles: Also known as the “first disease,” transmitted primarily by respiratory droplets carrying the Measles virus, the causative agent of the disease. This virus is a myelotropic, lymphotropic, and epitheliotropic negative-strand RNA virus. (10)

Scarlet fever: Also known as the “second disease.” Group A Streptococcus is the causative agent of scarlet fever, a beta-hemolytic bacteria that can cause red cell destruction. It is most commonly associated with pharyngitis. (11)

Hand, foot, and mouth disease: Most commonly caused by the coxsackievirus of the Enterovirus family. Coxsackievirus A16 and A71 are the serotypes most commonly implicated as causative agents. (12)

Roseola infantum: Also known as exanthema subitum or “sixth disease,” is caused by the Human Herpes virus 6, a virus found in the Herpesviridae family, closely related to human Cytomegalovirus and Human Herpes virus 7. (13)

Papular purpuric gloves and sock syndrome: Link to Parvovirus B19. Other report etiologies include the measles virus, EBV, CMV, HHV6, Coxsackie B6, and Hepatitis B. Parvovirus B19, however, is the only etiologic agent that has been found to be present in peripheral blood and skin biopsy specimens by PCR. (4)

Erythema infectiosum: Also known as the “fifth disease,” is caused by Parvovirus B19 infection, transmitted via respiratory droplets. (4)

Signs and Symptoms of Exanthematous Diseases (14, 15)

When assessing a child with exanthema, we should record their vital signs, as well as the different characteristics of the rash, their distribution on the body (diffused or localized, symmetric or asymmetric), where it lays down on the body (face, extremities, abdomen or trunk), if it itches or not, since it may help identify the pathogenic agent.

In addition, the patient may also have other viral symptoms, usually prodromic to the rash, that can help identify the cause of the illness:

  • Abdominal pain;
  • Body aches;
  • Fever;
  • Fatigue;
  • Headache;
  • Loss of appetite;
  • Sore throat;
  • Coryza (runny nose).

There are typical rashes for the different types of infection that we will describe in the following segment:

Varicella (16): one of the classic characteristics of Varicella rash is that it occurs in crops; therefore, we can typically see them at different stages of evolution. The rash begins as small red dots on the face, scalp, torso, upper arms, and legs, and over the next 10 to 12 hours, it progresses to small bumps, blisters, and pustules, reaching finally, the last stage with umbilication and scabs formation.

At the blister stage, intense pruritus is present. Blisters may occur on the palms, soles, and genital area. Commonly, visible evidence develops in the oral cavity and tonsil areas in the form of small ulcers, which can be painful and itchy.

Rubella (17, 18): The pink or light red rash consists of pinpoint erythematous, maculopapular, that classically begins on the face and or neck, spreads to the trunk and limbs, and become generalized in 24 hours. The rash usually last for 3 days and has a scarlatiniform disposition. The patient is infectious from 1 week before to 4 days after the appearance of the rash. There is mild pruritus.

Measles (17, 18, 20): Prodromal illness caused by Measles has the classic triad of the three “C’s”: Coryza, cough, and conjunctivitis. The rash is typically morbilliform with blanching erythema, macules, and papules that begin on the face, around the neck, the hairline, and behind the ears. The palms and the soles of the feet are usually spared. The rash last for 5-10 days and fades in the same way it appeared. Brownish discoloration (especially in patients of Caucasian descent) with fine desquamation (especially in malnourished patients) sometimes occurs as the rash fades. (18)

Before the rash, we can find bluish-white papules in the oral mucosa with the appearance of “grains of sand or rice,” called Koplik spots, which are the pathognomonic lesion for measles infection. However, Koplik spots are present in only 60% to 70% of patients and usually last 12 to 72 hours. (18) The incubation period is 1-2 weeks, and the child is contagious from the time they first develop symptoms until 4 days after the onset of the rash.

Scarlet fever (21): The rash develops on the upper trunk and spreads throughout the body, sparing palms and soles with characteristic paleness around the oral cavity. Contrary to some viral infection exanthema, the rash in Scarlet fever develops more quickly. The exanthema is characterized by confluent, erythematous, blanching, fine macules resembling a sunburn, and sandpaper-like papules.

In skin folds, Pastia lines may appear. Petechiae on the palate may develop, with erythematous swollen papillae with a white coating on the tongue and white strawberry tongue. After several weeks, the rash fades, and desquamation appears, especially in the face, skin folds, hands, and feet, lasting 4 to 6 weeks.

Hand, foot, and mouth disease (4): Patients usually manifest both enanthems and exanthems. The rash maculopapular, which progresses to vesicles for a short period to form a yellow-gray ulcer with an erythematous halo most commonly found in the hard plate, tongue, and buccal mucosa. Pain may interfere with oral intake.

The exanthema contains central gray vesicles that appear shortly after oral lesions in the hands and feet. They crust and disappear over 5-10 days without scaring.

Roseola Infantum (4, 22): It is characterized by the abrupt onset of the fever lasting a few days, after which there is an abrupt defervescence with the appearance of a rash of nonpruritic, rose-pink, blanching macules and papules that are surrounded by white halos.

This rash is very similar to the Measles rash, but we can differentiate them since in Roseola infantum, it first appears on the trunk and then spreads to the neck and extremities, whereas Measles rash starts on the face or mouth (Koplik spots) and moves downwards. Palpebral and periorbital edema (Berliner’s sign) is very common.

Papular purpuric gloves and socks syndrome (4): After the incubation period of 10 days, a systemic erythema and edema of the hands and feet progress to petechial and purpuric macules, papules, and patches that are followed by fine desquamation.

In this type of rash, there is a sharp demarcation at the wrist and ankles, characteristic of this disease. Rarely, the eruption may extend to nonacral sites. A lot of patients have polymorphous enanthem, including diffuse hyperemia, aphthae, petechiae, and erosions on the palate, pharynx, tongue, and possibly inner lips.

Erythema infectiosum (20, 22): The prodromic symptoms start several days before the erythematous bright red color facial rash, known as “slapped cheek,” appears. A few days later, it fades to mark the beginning of the second stage of the disease with pink patches and macules in a “lacey” reticular pattern, most often on the extremities and trunk.

The rash resolves after 1 to 6 weeks, but it may appear with sun exposure, injury, cold, or stress. When the rash disappears, we consider that the patient is no longer infectious.

Diagnosis of Exanthematous Diseases (18)

We should always start by assessing and documenting the vital signs and patient’s hydration status to be able to distinguish a critical patient from a milder case.

The diagnosis, in this case, is usually clinical, taking into account the type of rash, its location, evolution, and associated symptoms, considering the epidemiological history, personal history (prior diseases, immunological history, immunological status), clinical characteristics of the current disease, and any administration of medications before or during the rash.

To confirm the diagnosis, a serological test could be made for specific immunoglobulin M (Ig M) antibody of the agent we suspect, a four-fold or greater increase in specific Ig G titers between acute and convalescent sera, and if it can be taken isolation of the virus/bacteria from cultures of blood, or urine.

In several cases, more specific assays are performed, such as viral-specific PCR.

Management of Exanthematous Diseases (4, 18, 21, 23)

  • Treatment for viral rash infection is usually supportive. The initial management of the patient should aim to ease the discomfort that the symptoms may produce. Primarily, the focus should be on maintaining good hydration for the patient. Secondly, it should reduce the exposure of the virus to other people indicating airborne transmission precaution, especially in Measles. The use of moisturizer or antihistaminic may help reduce pruritus.
  • Among viral infections, Measles and Varicella typically require intervention with antiviral treatment and monitoring for systemic involvement and secondary bacterial complications. As an example, oral acyclovir may be used in selected patients diagnosed with Varicella.
  • Patients diagnosed with Erythema infectiosum should be kept from pregnant women because there is a risk of fetal death during pregnancy, as well as hand-foot and mouth disease that can lead to spontaneous abortion or intrauterine growth retardation when caught at the first-trimester pregnancy stage.
  • Bacterial exanthematous diseases do need appropriate antibacterial therapy with antibiotics due to the risk of complications and an increase in mortality rates. The first-line treatment for Scarlet fever is penicillin or amoxicillin. If the affected person has an allergy to penicillin, a first-generation cephalosporin, clindamycin, or erythromycin can be used.
  • Paracetamol will be the first line to reduce fever and discomfort in children. Also, the use of aspirin is contraindicated to treat viral illnesses in children because it has been associated with Reye syndrome (most commonly Varicella and influenza).

Vaccines and Immunization

  • As we said at the beginning of the article, routine vaccination is very important for the management of this condition and to avoid further severe complications. Thanks to these regulations, the rates of exanthematous diseases have diminished exponentially.
  • As an example, to eliminate measles, population vaccination rates must be over 93%. A single dose of measles vaccine given at or after the age of 1 is 93% to 95% effective at protecting against measles, whereas two doses given at appropriate intervals are nearly 100% effective.(24)
  • In the case of Varicella (chicken pox), routine vaccination prevents about 70-90% of infections and 95 % of severe diseases. Routine immunization is recommended, and immunization within three days of exposure may still improve outcomes in children. (16)
  • The Rubella vaccine is highly effective and safe, but incomplete rubella vaccination programs result in continued disease transmission, as evidenced by recent large outbreaks in Japan and elsewhere. (9)


The author does not report any conflict of interest


This information is for educational purposes, not to treat disease or supplant professional medical judgment. Physicians should follow local policy regarding the diagnosis and management of medical conditions.

See Also

Cellulitis Diagnosis and Management

Lower Urinary Tract Infections

Heart Failure With Preserved Ejection

Hypertensive Crisis

Dyspnea Due to Respiratory Causes

Approach to Chest Pain


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