Don’t Be Rash – Petechiae in Well Kids at St Emlyn’s

photo (30)A 6-month-old girl is brought by mum to the ED with a cluster of non-blanching spots to her right lower leg noticed while bathing her. She has a mild cough and snotty nose but is otherwise well – there is no history of fever and she is feeding well without diarrhoea or vomiting and with normal urine output. There is no history of trauma, no family history of coagulopathy, and an uncomplicated birth history. She is up-to-date with his immunisations and has never needed to attend ED before.

Examining her, you find a cluster of non-blanching spots, around five discrete lesions, approximately 2mm in diameter which do not disappear under pressure to the capillary bed. The rest of the examination is normal, apart from a runny nose. No other petechiae could be identified on top-to-toe examination. Her obs are normal.


We see lots of kids with rashes in ED, most brought out of an intrinsic anxiety that the rash represents something sinister – and none more so that those with spots which don’t fade.

Successful campaigns have raised public awareness of the “glass test” when kids have rashes, and although evidence for the presence or absence of a non-blanching rash as a specific or sensitive predictor of meningococcal sepsis is lacking, it is clear from both clinical experience and the published literature that non-blanching rashes – even in clinically well children – prompt parents to seek medical attention.


So… What are Petechiae?

Petechial haemorrhages are areas of pericapillary bleeding representing small extravasations of blood ranging in size from those invisible to the naked eye up to a diameter of 2mm. Larger lesions are termed “purpura” and may represent coalescence of several petechiae. They arise as a result of a number of pathophysiological processes, from increased capillary bed pressure (as seen when measuring non-invasive blood pressure) to increased consumption of clotting factors as seen in DIC, leading to platelet dysfunction and thrombocytopenia. The exact mechanism is unclear although it has been postulated that a combination of hypoxia, endothelial exposure to circulating toxins, and an element of venous obstruction underpin the development of petechiae in the context of various underlying causes.


Petechiae + Fever = ?

In children who have co-existing fever, or who are either objectively or subjectively unwell, the Emergency Physician’s approach is clearly mapped. Despite the evidence suggesting low incidence even among those presenting with petechial rashes, the high mortality of meningococcal sepsis mandates presumptive and immediate treatment alongside investigation, and this pathway is defined nationally in the UK and often locally too.


Should well children with petechiae have blood tests?

Petechiae in well babies occur commonly; a study published in 2002 found a prevalence of 27.6% of a cohort of 116 babies less than twelve months of age at child health surveillance clinics, predominantly to the trunk and lower limbs. Observation is the mainstay of ruling out early septicaemia, in addition to blood tests if there is demonstrable or historical pyrexia.

Many sources recommend blood test screening for well children with petechial and purpuric rashes, often with the aim of ruling out alternative pathology. It is important to remember that the differential diagnosis of petechiae does not stop at meningococcal disease and that other processes such as HSP and ITP require identification and investigation.

The exact combination of required laboratory tests is a subject of debate, with NICE recommending full blood count, coagulation profile, c-reactive protein (CRP), blood culture, glucose, blood gas and meningococcal PCR – although only in the presence of fever. Other studies suggest full blood count, CRP and blood culture only, or even just white cell count and CRP with four hours’ observation if the child does not meet the “ILL criteria” (irritability, lethargy, low capillary refill).

A sensible approach might be to consider other possible diagnoses and to perform tests which would reliably exclude them or diminish their post-test probability to an acceptable level. And if the child is completely well with no other concerns, they don’t necessarily need blood tests (although discussion with a senior or colleague together with careful safety-netting is advisable).


What are the other causes of petechiae in children?

  • Increased vascular pressure: cases of petechiae occurring in the distribution of the SVC are well documented and may follow choking, coughing, vomiting, convulsions, or other periods of transient increased intrathoracic pressure .


  • Mongolian blue spots: present in babies with increased melanocytes (darker skin), these are most likely to be found on the buttocks but may also appear on the legs, back, shoulders, sacral area and upper arms. Unlike bruises and petechiae, they tend not to have clear borders. Where one parent is attending, try to establish the ethnic origin of the other parent (if possible). Mongolian blue spots are more likely to be mistaken for bruises/NAI than petechiae.


  • Idiopathic/thrombotic thrombocytopenic purpura: increased platelet destruction occurs mediated by antibodies to platelet antigens. Petechiae, purpura and bruising are often present. A diagnosis necessitates exclusion of other causes. Platelet count is extremely low (although automated cell counters may be inaccurate due to inconsistent platelet sizes), and a blood film is usually required.


  • Henoch-Schonlein purpura: an IgA mediated systemic vasculitis often associated with arthritis/arthralgia and abdominal pain. Patients may have renal involvement. Diagnosis is uncommon in children under two years old. Palpable purpura are almost always present but some patients have a predominantly petechial rash.


  • Haematological causes: other causes of low platelets include sequestration and bone marrow aplasia. Primary leukaemia may cause an acquired bleeding tendency but other features would be expected, particularly apparent on full blood count and film. Haemorrhagic disease of the newborn should be considered in very young babies; it is important to elucidate a history of vitamin K administration in the neonatal period, as some mothers do refuse this.


  • Clotting disorders: causes of abnormal clotting with normal platelets include von Willebrand’s disease, coagulation factor deficiencies and liver disease (which has its own subset of causes). This paper includes a useful flow diagram for the investigation of purpura which classifies non-accidental injury as a precipitant of unexplained purpura (or petechiae) in children with normal platelet count, clotting screen and bleeding time. It is worth noting that von Willebrand’s disease and vascular purpura also appear in this subgroup.


  • Viral infections: in an observational study of 233 infants and children with a non-blanching rash, 89% of children did not have meningococcal infection. 55% of those who did not have meningococcal disease had petechiae beyond the distribution of the superior vena cava, attributed by the authors to vasculitis or disordered coagulation secondary to non-bacteraemic bacterial or viral infectons.


Anything else I should think about?

Some factors in the history and presentation of the child might lead to a suspicion of non-accidental injury. One study found a high proportion of children with non-accidental injury were brought by a third party (extended family member or teacher, for example). There are well documented prompts to consider non-accidental injury in event of;

  • Delay in presentation of the injury
  • Discrepant or absent history
  • History incompatible with the injury
  • Pattern of injury more suggestive of abuse
  • Repetitive injuries
  • Unusual parental behaviour or mood
  • Child’s demeanour, behaviour, or interaction with the parent/caregiver unusual
  • Disclosure by child or witness

Children aged under one year have the highest rate of physical abuse. Much research exists regarding the constellations of injuries and bruises in this group which might lead to a suspicion of non-accidental injury. Petechiae are often considered on the spectrum of bruising; when bruising is found on examination consider carefully:

  • The age of the child and developmental milestones

It is generally accepted that non-mobile children are unlikely to have bruises. Babies “do not injure themselves”, and blame attributed to siblings is rarely appropriate. A study of 973 well children under the age of 36 months found only 2.2% of non-mobile children had bruises, compared to 17.8% of cruisers and 51.9% who were walking. This systematic review of patterns of bruising found from pooled data that bruising in non-mobile babies was rare, occurring in <1%.

  • Site of bruising

In mobile children, bruises on bony prominences (particularly the anterior tibia and knee) and the forehead are common, reflecting frequent falls in those beginning to walk. Bruises in those aged 9 months to 4 years of age are more suspicious of non-accidental injury when found on other parts of the face, the head, neck, trunk or buttocks.

  • Patterns of bruising and petechiae

“Normal” bruises are not associated with petechiae in a child without an underlying medical or haematological problem. Petechiae which coexist with bruises are considered to have a high positive predictive value for non-accidental injury (80%: 95% confidence interval 64.1%-90.0%), although the absence of petechiae has no significance and their presence without bruising may be explained by a number of non-abusive mechanisms as previously discussed.

Linear petechiae may suggest the shape of a hand, having been formed by capillary rupture at the edge of injury from a high velocity slap. They may also represent specific mechanisms such as suction, squeezing, slapping, strangulation or suffocation. Blunt trauma may generate a negative impact of the offending object, outlined by petechiae, or deep to a constricting ligature . Petechiae to the earlobe commonly represents non-accidental injury, and linear petechiae may be associated with cultural practices such as cupping or coining.

Beware, though: The consensus of medical opinion is that bruises cannot be accurately aged by clinical assessment either in vivo or by photograph, with one study finding that aging to within 24 hours of occurrence is accurate less than 50% of the time, with poor interobserver reliability. There are no studies which discuss the changes in colour or appearance of petechiae over time.



Stop waffling and summarise!

Here’s how I would approach the well child with a petechial rash;

  1. Act primarily in the best interest of the child
  2. Consider meningococcal sepsis as a condition with high mortality which should not be missed
  3. Consider and try to exclude common alternative presentations as detailed
  4. Be mindful of non-accidental injury as a cause of isolated petechiae or those associated with bruising, and perform a top-to-toe examination for other lesions
  5. Consider the need to investigate with blood tests if any history of fever/illness/contacts (namely full blood count and film, coagulation screen to include PT, APTT, thrombin, fibrinogen and possibly bleeding time, CRP and blood culture if suspicion of occult bacteraemia is high)
  6. Have a low threshold for liaison with other agencies (paediatric team, children’s social care) to identify past engagement with services or prior aroused suspicion about non-accidental injury
  7. Refer for extended coagulation screening if initial tests are normal and a suspicious constellation of petechiae cannot be explained
  8. Remember that coagulation disorders and non-accidental injury are not mutually exclusive.

Your thoughts and approaches are welcome 🙂



And now: try this case from Life in the Fast Lane


but first ….before you go please don’t forget to…




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Cite this article as: Natalie May, "Don’t Be Rash – Petechiae in Well Kids at St Emlyn’s," in St.Emlyn's, July 1, 2013,

3 thoughts on “Don’t Be Rash – Petechiae in Well Kids at St Emlyn’s”

  1. Nice summary Natalie thanks. Good use of literature too with a number from the Cardiff team. I’ve been highlighting the Cardiff core info site to our juniors – it isn’t well known enough and is a useful resource.

  2. I have seen transfers to major university hospitals for petechiae in the bilateral upper arms in otherwise well appearing small children with fever. Apparently the lesions developed in the ED setting during w/u of fever.

    Of course, when you interview the parents, they report BP readings obtained in both upper extremities prior to the development of the rash.

Thanks so much for following. Viva la #FOAMed

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