OVERVIEW

What is roseola infantum?

Roseola infantum (Roseola) is a self-limiting clinical syndrome that occurs in children, also known as baby measles, type VI herpes virus rash, rose rash, sudden rash, sixth disease, fever rash, false rubella, or three-day fever. It is most common in children under 2 years old and is a common childhood exanthematous disease.

Roseola infantum is mostly caused by infection with human herpesvirus type 6. It is mainly characterized by sudden high fever in infants, often reaching above 39°C, lasting for about 3–5 days. After the fever subsides, a rash appears, usually in the form of red maculopapular eruptions^[1].

At what age do babies typically get roseola infantum? Are there seasonal differences?

Roseola infantum mostly occurs in infants under 2 years old and is more common in winter and spring^[2].

SYMPTOMS

What are the symptoms of roseola?

The classic symptoms of roseola are high fever followed by a rash, characterized by the rash appearing after the fever subsides^[1].

• High fever: The onset is sudden, with the child developing a high fever that can reach 39°C or above within hours, lasting for 3–5 days before dropping abruptly. The rash appears after the fever subsides^[2].
• Rash: The rash consists of rose-colored maculopapules (macules are flat, while papules are raised), 2–3 mm in diameter^[2], which fade when pressed. The rash typically starts on the neck and trunk, quickly spreading to behind the ears, buttocks, and proximal limbs (such as the upper arms and thighs). The lesions are scattered, rarely merging, and usually appear all at once within a day, fading in 1–2 days. In some cases, the rash may take up to three days to fully develop.
• Loss of appetite: During the illness, the child may experience reduced appetite, occasional diarrhea, vomiting, or other digestive symptoms, but their mental state generally remains unaffected^[2].
• Other accompanying symptoms: Some children may exhibit fatigue, irritability, mild diarrhea, runny nose, cough, decreased appetite^[2], eyelid swelling, or swollen lymph nodes in the neck, behind the ears, or the back of the head.

What other diseases can roseola cause?

Complications of roseola in children are rare but may include the following^[3]:

• Febrile seizures: Infants under 1 year old may experience seizures during high fever, characterized by twitching of the limbs and facial muscles, upward rolling of the eyes, unresponsiveness, foaming at the mouth, and bluish skin.
• Increased intracranial pressure: The child may appear lethargic or experience vomiting.
• Pneumonia: The child may develop a cough with phlegm after the fever.
• Hepatitis: The child may appear "drowsy" and exhibit symptoms such as loss of appetite and vomiting.

CAUSES

What causes roseola in infants?

Roseola is caused by viral infections, most commonly human herpesvirus 6 (HHV-6)^[3].
Additionally, roseola may also be triggered by human herpesvirus 7 (HHV-7), enteroviruses (coxsackievirus A, coxsackievirus B, and echovirus), adenovirus, parainfluenza virus type 1, and others.

Is roseola contagious? How is it transmitted?

Roseola can spread through airborne droplets^[3], primarily via respiratory secretions, saliva, or the fecal-oral route.

What factors may contribute to the occurrence of roseola?

Decline in maternal antibodies: After six months of age, antibodies passed from the mother decrease, making infants more susceptible to infections that may trigger roseola.
Improper care: Human herpesvirus 6 can spread through airborne droplets^[2], and infants may contract the virus by contact with infected individuals. Caregivers who take young children to crowded places increase the risk of infection, potentially leading to roseola.

DIAGNOSIS

What tests are needed for roseola infantum?

Doctors can usually diagnose roseola infantum based on the symptoms of fever followed by a rash, combined with some simple physical examinations. Laboratory evaluation is generally not required. However, immunocompromised children or those with atypical symptoms or complications may need virological tests, including HHV-6, HHV-7, enterovirus, adenovirus, and parainfluenza virus type 1.

What diseases should be differentiated from roseola infantum?

Rubella^[3]: Rubella also presents with symptoms such as fever and rash, but the rash appears simultaneously with the fever and typically starts on the face before spreading to other parts of the body. In contrast, roseola infantum is characterized by a rash appearing after the fever subsides. The two diseases can be distinguished by differences in clinical manifestations, such as lymphadenopathy.

• Kawasaki disease^[3]: Also known as mucocutaneous lymph node syndrome, Kawasaki disease, like roseola infantum, often occurs in children under five years old. Symptoms include persistent fever, rash, red lips, peeling of the palms and soles, and lymphadenopathy. However, in Kawasaki disease, the rash appears at the same time as the fever, which differs from roseola infantum. Therefore, if a child develops a rash while having a fever, immediate medical attention is necessary. Doctors can differentiate between Kawasaki disease and roseola infantum by examining changes in the extremities, conjunctiva, and oral mucosa.
• Measles^[3]: Measles shares similar symptoms with roseola infantum, including high fever and rash. However, measles is typically preceded by prodromal symptoms such as runny nose, cough, and Koplik spots. The rash usually starts on the face and then spreads to other parts of the body. The two diseases can be distinguished by differences in symptoms such as cough and conjunctivitis.

When should you seek medical attention for roseola infantum?

Roseola infantum can only be diagnosed after the rash appears, making it difficult to determine the cause during the initial fever phase. This can be particularly challenging for new parents. Fortunately, roseola infantum is usually not severe, and parents can monitor the child at home initially.

Seek medical attention immediately if any of the following occur, as a doctor will need to determine whether another condition is present:

• A rectal temperature exceeding 38°C (100.4°F) in infants under three months, regardless of how the child appears;
• Fever lasting more than three days in children aged three months to three years, especially if the child seems very ill, irritable, or refuses to drink water;
• A rectal temperature exceeding 40°C (104°F) or an armpit temperature exceeding 39.4°C (102.9°F);
• Seizures caused by fever (i.e., febrile seizures);
• New rashes appearing alongside fever;
• Fever accompanied by underlying conditions such as heart disease.

TREATMENT

Which department should I visit for roseola infantum?

Pediatrics, Dermatology.

How is roseola infantum treated?

Symptomatic treatment

• Fever: Ensure the child gets plenty of rest and provide adequate fluids and nutrition^[2]. Prioritize physical cooling methods, such as wiping the child's body with lukewarm water to help dissipate heat, and ensure warmth after wiping. Alternatively, wrap an ice pack in a soft dry towel and place it on the forehead, armpits, groin, or neck to aid in reducing fever.
• Rash: The rash associated with roseola infantum is not itchy, so the child typically won’t scratch it. However, parents should prevent the child from accidentally scratching the rash out of curiosity. Monitor and guide the child, keep the rash area clean and dry, change clothes frequently, and avoid infection.

Medication

• Granulocyte-boosting drugs: Children often experience granulocytopenia. To address this, granulocyte-boosting medications such as oral leukocyte-raising drugs or subcutaneous rhG-CSF injections may be used^[4].

Does roseola infantum leave any sequelae?

If fever is managed properly and medical attention is sought promptly for any abnormalities, sequelae are generally not expected.

Most children with roseola infantum recover on their own and do not experience long-term complications^[1].

DIET & LIFESTYLE

What should be paid attention to in daily life for roseola infantum?

Allow the child to rest as much as possible^[2]. Even with a rash, bathing, using fans, or air conditioning is not prohibited. Dry the child promptly after bathing to avoid catching a chill.

During the high fever phase of roseola infantum, the child may become irritable or fussy. Caregivers should provide comprehensive care, maintain an appropriate room temperature and humidity, and change clothes promptly if they become damp from sweat.

Stay by the child's side, soothe their emotions, and distract them by telling stories to help them get through the high fever period smoothly.

What dietary precautions should be taken for roseola infantum?

Ensure adequate hydration. Even if the child has a poor appetite, sufficient nutrition should be provided^[2]. If the child is still breastfeeding, encourage more foremilk intake, as it helps replenish fluids and provides immune-boosting components from breast milk.

PREVENTION

Is there any way to prevent roseola infantum?

Feed children reasonably and take them outdoors for exercise to promote physical development and build strong resistance.

Avoid taking infants to crowded places, and wash hands and change clothes before contact.

Keep infants' living environment clean, tidy, and at suitable temperature and humidity.