The six childhood exanthems, also known as the “sixth diseases” or “sixth exanthems,” are a group of viral infections that commonly affect children. An exanthem refers to a widespread rash that occurs on the skin as a symptom of an underlying medical condition, typically a viral infection. These rashes can have various appearances, including macules (flat red spots), papules (raised bumps), vesicles (small fluid-filled blisters), or plaques (raised, flat-topped areas).
In the context of childhood diseases, exanthems are often associated with specific viral infections and are sometimes referred to as “childhood exanthems” which are characterized by distinct rash patterns and other symptoms.
Measles
Measles is caused by the measles virus (MeV), which belongs to the genus Morbillivirus within the family Paramyxoviridae. It is a single-stranded, negative-sense RNA virus.
Measles typically starts with fever, cough, runny nose, red eyes, and sore throat, followed by a characteristic red rash that usually starts on the face and spreads to the rest of the body.
- Fever: Measles typically begins with a high fever, often exceeding 101°F (38.3°C).
- Rash: The rash usually appears a few days after the fever starts. It begins as flat, red spots that often blend together and become raised. The rash typically starts on the face and spreads downward to the trunk and limbs.
Rubella
Rubella, also known as 3 day measles or German measles, is a contagious viral infection caused by the rubella virus.
Mild fever, rash that starts on the face and spreads to the rest of the body typically clearing in 3 days, swollen and tender lymph nodes, especially behind the ears and at the back of the head, headache, runny or stuffy nose, red eyes (conjunctivitis).
- Fever: Fever may be mild or absent in some cases.
- Rash: The rash typically appears 2 to 3 days after the onset of fever. It starts as pink or light red spots that may merge and become more pronounced. The rash usually begins on the face and then spreads to the trunk and limbs.
Scarlet Fever
Scarlet fever, also known as scarlatina, is a bacterial infection caused by group A Streptococcus bacteria, specifically Streptococcus pyogenes.
Sore throat, fever, red and swollen tonsils with the characteristic rash that feels like sandpaper and typically starts on the chest and abdomen before spreading to other parts of the body, except for the face. Sometimes reddening of the tongue, often with a white coating initially (known as “strawberry tongue”), which later becomes bright red
- Fever: Scarlet fever is usually accompanied by a high fever, often above 101°F (38.3°C).
- Rash: The characteristic rash of scarlet fever appears as tiny, red spots that may feel rough to the touch. It often starts on the chest and abdomen before spreading to other parts of the body.
Erythema Infectiosum (Fifth disease)
Erythema infectiosum, also known as slapped cheek syndrome, is a viral illness caused by parvovirus B19.
A distinctive red rash on the cheeks that gives the appearance of “slapped cheeks,” hence the alternative name “slapped cheek syndrome.” After several days, a lacy rash may develop on the trunk and limbs. Some individuals may experience mild flu-like symptoms such as fever, headache, and fatigue.
- Fever: Fever may occur, but it is typically mild or absent in many cases.
- Rash: The rash of fifth disease usually begins as bright red or rosy cheeks, giving the appearance of “slapped cheeks.” Later, a lacy or reticulated rash may develop on the trunk and limbs.
Roseola Infantum (Sixth disease)
Roseola, also known as roseola infantum or sixth disease, is a viral illness caused by human herpesvirus 6 (HHV-6) or, less commonly, human herpesvirus 7 (HHV-7).
Sudden high fever, which can last for several days. vAfter the fever breaks, typically within 3 to 5 days, a distinctive rash appears that consists of small, pink, flat or slightly raised spots or patches that usually begin on the trunk and spread to the neck, face, and limbs. The rash typically lasts for 1 to 2 days and may come and go before disappearing completely.
In addition to fever and rash, other symptoms of roseola may include irritability, mild diarrhea, runny nose, cough, and swollen lymph nodes.
- Fever: Roseola typically starts with a sudden high fever, often above 102°F (38.9°C), which lasts for several days.
- Rash: After the fever resolves, a pink, flat or slightly raised rash may appear on the trunk, neck, face, and limbs. The rash is usually not itchy and may last for 1 to 2 days.
Varicella (Chickenpox)
Caused by the varicella-zoster virus, chickenpox presents with an itchy rash consisting of small, fluid-filled blisters that eventually crust over. Other symptoms may include fever, headache, and fatigue.
- Fever: Chickenpox often starts with a moderate fever, which may precede the rash.
- Rash: The rash begins as small, red spots that quickly develop into fluid-filled blisters (vesicles). These blisters then crust over and scab. The rash typically starts on the face, scalp, and trunk before spreading to other parts of the body.
