Paediatric Rashes

Last Updated on by frcemuser

Childhood exanthems


No. Other names Aetiology (ies)
First disease Rubeola,


Second disease Scarlet Fever,


Third disease Rubella,

German measles,

3-day measles

Rubella virus
Fifth disease Erythema infectiosum Parvovirus B19
Sixth disease Exanthem subitum,

Roseola infantum,

Human Herpes Virus 6B or

Human Herpes Virus 7

Common rash descriptions

Lesion Type Description
Macule Circumscribed area of change in normal skin color, with no skin elevation or depression; may be any size
Papule Solid, raised lesion up to 0.5 cm in greatest diameter
Nodule Similar to papule but located deeper in the dermis or subcutaneous tissue; differentiated from papule by palpability and depth, rather than size
Plaque Elevation of skin occupying a relatively large area in relation to height; often formed by confluence of papules
Pustule Circumscribed elevation of skin containing purulent fluid of variable character (i.e., fluid may be white, yellow, greenish or hemorrhagic)
Vesicle Circumscribed, elevated, fluid-containing lesion less than 0.5 cm in greatest diameter; may be intra-epidermal or sub-epidermal in origin
Bulla Same as vesicle, except lesion is more than 0.5 cm in greatest diameter


Petechial/purpuric rashes

Petechiae are small, red lesions caused when capillaries leak blood into the skin. Petechiae larger than 0.5 cm are purpura


Causes for Rash

Maculopapular rashes

Causes of maculopapular eruptions are:

  • Measles (rubeola)
  • Rubella
  • Erythema infectiosum (fifths disease)
  • Exanthum subitum (roseola)
  • Lymes disease
  • Pityriasis
  • Drug related eruptions
  • Steven Johnsons Syndrome
  • Erythema Multiforme
  • Meningiococcaemia


Diffuse erythema with desquamation:

  • Scarlet fever
  • Toxic shock syndrome and scalded skin syndrome
  • Kawasaki disease


Vesiculobullous/ pustular eruptions:

  • (Diffuse) Varicella zoster
  • (Diffuse) disseminated Gonnococaemia
  • (Local) hand foot and mouth
  • (Local)Herpes zoster
  • Staphylococcal bacteraemia
  • Rickettsia


Purpuric lesions

  • Meningococcal disease (non Balancing )
  • Henoch–Schönlein purpura.
  • Thrombocytopenia.
    • Idiopathic thrombocytopenic purpura;
    • Leukemia;
    • Septic shock;
    • Aplastic anemia.
  • Some viral illnesses.
  • Forceful coughing or vomiting may cause petechiae of the face.

Measles (rubeola)

  • a generalized maculopapular rash > 3 days
  • The rash begins at the head and goes down
  • A cough, coryza, conjunctivitis (three “Cs”)
  • Koplik spots
  • spread by droplet spread or less commonly by aerosol spread
  • The investigation is performed using oral fluid or serum sampling for measles IgM acute cases measles can be detected using throat swabs or in the urine
  • Measles is a notifiable illness and notification is required based on clinical suspicion.
  • Incubation period is approximately 7-21.nfectivity is several days before the onset of the symptoms up to four days after the appearance of an erythematous maculopapular rash.
  • Children diagnosed with measles should be kept off school until 5 days after the appearance of the rash.
  • Symptomatic treatment
  • Complications
    • Otitis media
    • Bronchopneumonia
    • Laryngotracheobronchitis
    • Diarrhea
    • Acute encephalitis
    • Sub-acute sclerosing pan encephalitis
  • Current MMR vaccinations are administered at 12-15 months of age and 3 to 5 years of age.


Scarlet fever

  • A specific, toxin-producing Group A beta-hemolytic streptococci 
  • a sore throat, headache, fever, tender cervical lymphadenopathy and malaise
  • Sandpaper rash starts 12-72 hours after fever
  • Flexor creases (Pastia’s lines) then move to trunk and extremities
  • Strawberry” tongue (fine papules on the tongue) Skin peeling (palms and soles)
  • spread by aerosol or droplet spread
  • The incubation period for scarlet fever is usually 2-5 days. The infectivity period is about 5 days from when the patient is given antibiotics
  • Diagnosis —throat swab, Streptococcal antibody test, increasing ASO titer
  • Scarlet fever is a notifiable disease and notification is required based on clinical suspicion.
  • scarlet fever should be excluded from school for 5 days following the commencement of antibiotics
  • Treatment — oral penicillin — 10 days (penicillin V or erythromycin or cephalosporin)
  • Complications: Sinusitis, mastoiditis, peritonsillar abscess, pneumonia, meningitis, osteomyelitis, septic arthritis, cerebral abscess. Septicaemia, myocarditis and toxic shock-like syndrome. Glomerulonephritis and acute rheumatic fever.


Rubella (German Measles)

  • Acute viral illness (fever, sore throat, headache)
  • Also called “three-day measles”
  • Rash (pink macules spread from head to feet)
  • Prominent lymphadenopathy posterior auricular (mono also can cause this), cervical, occipital
  • spread by airborne transmission or droplet spread from 7 days before to around 7 days after the onset of the rash. The incubation period is around 2 weeks after which a prodrome of headaches, fever and lymphadenopathy occur.
  • Rubella is a notifiable disease and notification is required based on clinical suspicion. Children diagnosed with rubella should remain off school for at least 5 days following the onset of the rash.
  • Investigation: IgG and IgM assays are used
  • Complications
    • Arthritis (immune complex)
    • Encephalitis
    • 1st-trimester pregnancy (congenital defects) 
      • Cataracts
      • Microopthalmos
      • Congenital glaucoma
      • Patent ductus arteriosus
      • Peripheral pulmonary artery stenosis
      • Sensory neural hearing impairment
  • Treatment symptomatic



Erythema Infectiosum (Fifth Disease)

  • Human Parvovirus B19 / spring
  • Fever (sometimes), myalgias, diarrhoea, URI symptoms / preschool age
  • The virus is predominately spread in respiratory droplets but can also pass from mother to foetus and in blood transfusions.
  • Rash abrupt onset, bright red cheeks (“slapped cheeks”) then spread to arms and legs second day (spare chin and eyelids)
  • Rash is “lace-like” on limbs, trunk/ may come and go 1-2 weeks
  • The incubation period for erythema infectiosum is usually between 4 and 14 days but can be as long as 21 days.
  • The infectivity period commences at exposure and lasts until the symptoms appear, i.e. at 4-14 days.
  • Investigations: IgM antibodies appear around 10 days post infection and remain detectable for up to 2-3 months. IgG antibodies appear at about 14 days post infection and remain for life.
  • Usually a self-limiting disease / symptomatic treatment
  • Pregnant women are at risk for fetal infection. Viral transmission in pregnancy is more likely to occur during the first and second trimester. Intravenous immunoglobulin, which contains pooled neutralising anti B19 antibody has been used to treat immunocompromised patients
  • Complications: Transient aplastic crises can occur


Roseola Infantum

  • Also called exanthem subitum Human herpes viruses (HHV) 6 and 7
  • Common at ages 6-18 months
  • respiratory illness, 3-5 days of fever and cervical lymphadenopathy
  • High fever (3-4 days), then a characteristic rash, which appears as the fever disappears.
  • Febrile seizures are common
  • Pink macules and papules on the trunk
  • May spread to neck, face, extremities
  • The incubation period for exanthem subitum is from 5-15 days.
  • Treatment symptomatic
  • Complications: Encephalitis,Hemiplegia


Kawasaki’s Disease

  • Also called mucocutaneous lymph node syndrome
  • Acute, febrile, exanthematous disease of children (age 2-5, males, Asian)
  • Self-limited vasculitis with a predilection for coronary arteries
  • Cause unknown possibly an immune response to bacterial infection, since it occurs in outbreaks
  • Important to make this diagnosis
  • Major criteria fever >5 days PLUS 4 of the following
    • Conjunctival injection (bilateral)
    • Strawberry tongue, fissures, lips cracked
    • Desquamation or swelling of fingers and toes
    • Erythematous rash (starts on palms and soles)
    • Enlarged (15mm or greater) cervical lymph nodes
  • Increase WBC,increase ESR,increase platelets
  • Coronary artery aneurysms
  • Treatment aspirin, IV immunoglobulin
  • Complications:
    • Coronary artery thrombosis and coronary and peripheral
    • artery aneurysm
    • Myocardial infarction
    • Myopericarditis
    • Congestive heart failure
    • Hydrops of gall bladder
    • Aseptic meningitis
    • Arthritis
    • Sterile pyuria (urethritis)
    • Thrombocytosis
    • Diarrhea
    • Pancreatitis
    • Peripheral gangrene


Chickenpox (Varicella Zoster)

  • Varicella zoster virus
  • Fever, malaise, URI
  • Macules, papules, vesicles, crusts (lesions of various ages)(dewdrops on a rose petal = image
  • prolonged fever > 4 days should prompt the suspicion of complications of Varicella such as secondary bacterial sepsis
  • Incubation is from 10 to 21 days. The period of infectivity is from the time when symptoms first appear until all lesions have crusted over. This is usually around 5-6 days after the onset of the illness. Most crusts will disappear by 20 days.
  • Complications (mostly adults) pneumonia,encephalitis, otitis media, Bacteraemia
  • Treatment acyclovir or analogs
  • Avoid salicylates (Reye’s syndrome)
  • Prevention: immune globulin if pregnant or  immunocompromised, vaccine in kids
  • The risks to the mother are the highest in the third trimester and the risks to the foetus are the greatest in the first and second trimester.
  • Varicella zoster immunoglobulin should be given to neonates whose mothers develop the rash 7 days before or 7 days after the delivery, to reduce the risk of severe neonatal Varicella.
  • Neonates presenting with a chickenpox rash should be admitted for aciclovir.
  • Failure to recognize complications such as secondary streptococcal and staphylococcal infection or to appropriately manage high-risk groups


Purpuric lesions




Refer Meningitis

Henoch-Schönlein purpura (HSP)

  • Henoch-Schönlein purpura (HSP) is an IgA-mediated, autoimmune hypersensitivity vasculitis of childhood
  • The peak prevalence is in children aged 4 – 6 years.
  • patients have a preceding upper respiratory tract infection (URTI).
  • causes reddish-purple purpura on the backs of the legs, buttocks, trunk, and back, and may be associated with joint pains and swelling (especially in the knees and ankle), and gastrointestinal symptoms.
  • Abdominal pain and bloody diarrhea may precede the typical purpuric rash. HSP may also cause nausea and vomiting.
  • treatment for most patients remains primarily supportive
  • Renal involvement occurs in 50% of older children may progress to end-stage kidney disease.
  • Other rare complications include myocardial infarction, pulmonary hemorrhage, pleural effusion, intussusception (in 2-3% of patients), gastrointestinal bleeding, bowel infarction, seizures and mononeuropathies.


Acute idiopathic thrombocytopenic purpura (ITP)

  • Usually seen in children
  • Caused by a reaction to a viral infection resulting in the production of antibodies against platelets
  • Sx: easy bruising, sudden onset of petechiae, nosebleeds, menorrhagia
  • Splenomegaly may be seen on examination but this is rare
  • Usually self–limiting, with about 90% of children recovering within 6 months
  • Steriods,Immunoglobulin,anti-D,Rituximab

Coagulation disorders

  • Haemophilia A (factor VIII deficiency) and B (factor IX deficiency)
  • X-linked conditions
  • Features depend on the level of clotting activity, and include spontaneous haemarthrosis, especially of the knees, ankles, and elbows; and muscle haematomas in severe haemophilia. Increased or delayed bleeding with injury or postoperatively is typical of milder disease.


Von Willebrand disease (VWD)

  • The most common inherited coagulation disorder, with an incidence of up to 1% in the general population.
  • Inherited as an autosomal dominant disorder (equally common in males and females).
  • Typically presents with mild to moderate mucocutaneous bleeding, such as nosebleeds, menorrhagia, or prolonged bleeding after surgical incisions or dental procedures.
Notification status of diseases 
Name of Disease Status
Measles Notifiable
Scarlet fever Notifiable
Rubella Notifiable
Erythema infectiosum Non-notifiable
Exanthem subitum Non-notifiable
Chicken pox Non-notifiable
Gianotti-Crosti syndrome Non-notifiable

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