Davis, T. Perilous Pinhead Polkadots, Don't Forget the Bubbles, 2013. Available at:
A 3 week-old newborn is brought in to the emergency department by her worried parents. A non-blanching rash has appeared overnight….
This quiz is reproduced with the permission of the very lovely Life in the Fast Lane team.
Q1. Describe the rash.
There is a widespread petechial rash evident on the face, neck and hands.
In some areas the petechiae appear to have progressed to purpura. The child may also be jaundiced.
Q2. What are petechiae and purpura?
These are non-blanching erythematous (reddish) skin lesions resulting from the extravasation of blood due to intradermal capillary leakage.
Petechiae are lesions the size of a pin-head (different sources say less than 2 mm or 3 mm, others up to 5 mm) and purpura are lesions that are larger than this (and may or may not be palpable).
Q3. What are the possible causes of this type of rash?
The causes of a petechial or purpuric rash can be grouped into 4 main categories:
- Infection —
serious bacterial illnesses (classically meningococcemia, but also others infections such as streptococcus, H. influenzae and infective endocarditis)
viral infections (e.g. influenza, measles, enteroviruses and parvovirus)
rickettsiae (e.g. Rocky Mountain Spotted Fever in North America, Epidemic typhus and Queensland tick typhus)
- Mechanical —
coughing or vomiting (limited to the head and neck regions)
local pressure or tourniquet application (e.g. petechiae distal to the tourniquet)
- Hematological —
thrombocytopenia (platelets <100 x 10E9/L) — e.g. ITP (immune thrombocytopenic purpura), leukemia and hypersplenism.
platelet dysfunction — e.g. congenital, drugs and renal failure.
- Vascular —
vasculitis — e.g. Henoch-Schonlein purpura
scurvy (classically perifollicular pupura on the lower limbs)
drugs e.g. steroids
The rash can results from the following mechanisms:
- mechanical capillary injury
- impaired haemostasis
- septic emboli or invasion of the capillary walls
- microbial toxin-induced capillary damage
- immune complex deposition
Q3. What is the likelihood of a serious bacterial illness in a child with type of rash?
The presence of a petechial rash is classically described as a feature of meningococcemia. The approach to a child with this type of rash in the emergency department is focused on identifying and treating serious bacterial illnesses early, as well as identifying important hematological/ vascular diseases.
In reality, in the modern post-vaccination era, over 90% of petechial rashes in well-appearing children are probably the result of a relatively benign viral illness. Some studies suggest that rates of serious bacterial illness are as low as 2% or less.
However, if the child appears unwell the likelihood will be significantly higher, and missing a serious bacterial illness could be catastrophic…
Q4. What illness should be considered if this type of rash is present in a ‘glove-and-socks’ distribution?
The ‘glove-and-sock’ syndrome is said to be typical of a parvovirus infection, with petechiae affecting the hands and feet. However, during a parvovirus B19 outbreak, the virus may be a common cause of a generalized petechial rash. Infection is associated with arthralgia, leukopenia and thrombocytopenia. Other presentations include ‘slapped cheek syndrome’ in children and aplastic crises.
Q5. How will you manage an otherwise well febrile child if the rash affects only a small area of skin?
The approach described is based on that of the Royal Children’s Hospital in Melbourne:
- Mechanical cause suspected:
If there is a convincing history of a mechanical cause (e.g. recurrent vomiting or coughing) and the petechiae are localised to the appropriate region of the body (e.g. SVC distribution) then reassurance and appropriate management of the underlying condition is all that is required.
- Non-mechanical cause suspected:
In the absence of a mechanical etiology, the following measures are taken:
— check FBC and CRP and obtain a blood culture (consider a coagulation profile)
— observe the child for 4 hours in the emergency department
The child can be discharged with follow up the next day if:
— the child remains well
— WBC is in the 5-15 x 10E6/L range and CRP<8
— no significant thrombocytopenia or evidence of coagulopathy
Q6. What if the child appears well, but has already been treated with antibiotics?
This controversial, however I would generally elect to manage as in Q5 above. The main concern is inadequate treatment of a partially treated serious bacterial illness.
Q7. What features should you use to decide if a child with this type of rash is ‘well’ or ‘unwell’?
A child with a petechial rash should be considered ‘unwell’ if any of the following are present:
- the child is irritable or lethargic
- the child has abnormal vital signs — tachycardia, tachypnea or SpO2 desaturation, hypotension or abnormal pulse pressure
- the child has poor peripheral circulation — cool peripheries, capillary return time > 2 seconds
- It’s probably reasonable to add: if the doctor, nurse or the parents think the child is unwell regardless of the above…
A ‘well’ child who is found to have the following should also be treated as ‘unwell’:
- the petechiae progress in extent during the 4 hours of observation in the emergency department
- purpura (lesions >2 mm) develop —
however, the child may be treated for Henoch-Schonlein purpura if he or she is well with palpable purpura in the classic distribution (buttocks and lower lower limbs) with or without arthralgias or abdominal pain.
- abnormal laboratory parameters —
WBC <5 or >15 x 10E6/L
Q8. How will you manage the unwell child with this type of rash?
This should be treated as a potentially life-threatening emergency.
The child is assumed to have a serious bacterial illness such as meningococcemia and is treated as follows:
- managed in an area equipped for resuscitation.
- attend to ABCDEFG (don’t ever forget glucose!) H (and get help…)
- fluid resuscitation as required.
- obtain FBC, CRP and blood culture and other investigations as indicated.
- treat with a third generation cephalosporin (e.g. ceftriaxone or cefotaxime) as soon as possible.
- admit to hospital — consider the need for PICU admission.
Q9. What if the laboratory investigations show that the child has thrombocytopenia?
Thrombocytopenia can result from infectious causes (viral or bacterial septicemia), immune thrombocytopenic purpura (ITP) or other hematological disorders such as leukemia.
ITP is the likely diagnosis when there is:
- significant thrombocytopenia with an otherwise normal FBC, and
- no hepatosplenomegaly or lymphadenopathy
in an otherwise well child with a petechial or purpuric rash.
- Edmonson MB, Riedesel EL, Williams GP, Demuri GP. Generalized petechial rashes in children during a parvovirus B19 outbreak. Pediatrics. 2010 Apr;125(4):e787-92. Epub 2010 Mar 1. PMID: 20194277.
- Klinkhammer MD, Colletti JE. Pediatric myth: fever and petechiae. CJEM. 2008 Sep;10(5):479-82. PMID: 18826740.
- Mandl KD, Stack AM, Fleisher GR. Incidence of bacteremia in infants and children with fever and petechiae. J Pediatr. 1997 Sep;131(3):398-404. PMID: 9329416.
- Marx JA, Hockberger R, Walls RM. Rosen’s Emergency Medicine: Concepts and Clinical Practice (7th edition), Mosby 2009. [mdconsult.com]
- Royal Children’s Hospital Melbourne. RCH Clinical Practice Guidelines — Fever and Petechiae.
- Wells LC, Smith JC, Weston VC, Collier J, Rutter N. The child with a non-blanching rash: how likely is meningococcal disease? Arch Dis Child. 2001 Sep;85(3):218-22. PMID: 11517104; PMCID: PMC1718924.