In this post, I link to and excerpt from the PedsCases‘ [Link is to the latest content] podcast and show notes, Approach to Purpura, by Samanta Lam, Jan 26, 2018.
All that follows is from the above resource.
This podcast presents a general approach to purpura. Listeners will learn about symptoms, history and physical exam findings, and the differential diagnosis for purpura in children. This podcast has been developed by Dr. Samantha Lam, a medical graduate of the University of Alberta, with Dr. Melanie Lewis, a general pediatrician and Associate Professor at the University of Alberta and Stollery Children’s Hospital in Edmonton.
All that follows is from the script of Approach To Purpura from PedsCases.
Approach to Purpura
Developed by Samantha Lam and Dr. Melanie Lewis for PedsCases.com.
January 26, 2018
Samantha: Let’s start with a clinical case.
Dr. Lewis: You are a clinical clerk working in the emergency room when a father brings his daughter in because she became increasingly lethargic over the past 24 hours. She had been sick with nausea and vomiting, and developed a rash.
Samantha: Given this story, as a student, what do you expect to find on exam?
Dr. Lewis: When you see her in the ER, she looks quite sick. She appears to be quite sleepy and does not respond to your questions and examination. You immediately notice a
non-blanchable violaceous spot on her torso, and her limbs were mottled. You observe that her vitals show a heart rate of 150, a blood pressure of 90/50, a respiratory rate of 35 and a temperature of 40C.
It’s easy to brush off a rash since they are common and often benign. But with purpura, you must always rule out potentially dangerous life threatening clinical conditions.
The objectives of this PedsCases podcast are to: 1) learn how to identify and describe a purpuric rash; 2) develop an approach to a making a differential diagnosis to a purpuric rash; and 3) learn to identify common, benign, and dangerous presentations of a purpuric rash and 4) describe the corresponding basic management.
Definition of Purpura
Purpura refers to a non-blanchable purple rash caused by a hemorrhage into the skin and mucosal membranes, which is the reason why this rash is non-blanchable. Since the problem is with bleeding, think of the problem as either a disruption to hemostasis or the vasculature. The lesion is described differently depending on size: petechiae if it is less than 4 mm, purpura if it is between 5 mm to 9 mm, and ecchymoses it is more than 10mm1.
Approach the differential diagnosis in a child with purpura
One way to form a differential diagnosis is to consider the clinical presentation of the child and appearance of the rash. A sick or febrile child hints at something serious that needs immediate management, such as infection, disseminated intravascular coagulation, and hemorrhage, while a well appearing child with purpura may indicate vasculitis, thrombocytopenia, or mechanical causes of bleeding. Next, determine if the purpura is palpable.
History and Physical Exam
History and Physical Exam
Samantha: What are key questions to figuring out what is causing purpura?
Dr. Lewis: Go back to the basics: history and physical exam. Immediately look to see if the child is sick and requires immediate care. A child is sick if they are unstable and have abnormal vital signs, constitutional symptoms, altered level of consciousness, increased work of breathing or poor perfusion. Get help if you see these signs.*
*[These children need immediate emergency care and stabalization.]
If not [sick], take a history and figure out the onset of the rash, course of illness, and baseline health of the patient. Questions about travel, environmental exposures, vaccination status and sick contacts can point to infection. Ingestion of certain medications or drugs can suggest a potential reaction
or bleeding. A family history of a bleeding disorder can indicate an inherited bleeding disorder. It is critical to know if there are constitutional symptoms. Fever and lethargy point to an infection, while weight loss, bone pain, joint pain, pallor, lymphadenopathy and splenomegaly suggest a malignancy.
Samantha: Are there any specific physical exam findings that students’ should look for that can help form their differential?
Dr. Lewis: Start with vitals, vitals, vitals! And assess their circulation, airway and breathing. On the physical exam, expose the child to inspect the entire skin surface. Describe any rash you find using the SCALDA acronym: size, color, arrangement, lesion morphology,
distribution, and adjunct structures. Do not forget to look behind the ear, in the pelvic region and at the mucous membranes. Specifically, look for lymphadenopathy, splenomegaly and pain to the joints and bones.
Samantha: Especially with a history with vague unspecific symptoms, a thorough physical exam is important to forming a differential.
Samantha: Now, let’s start with a presentation that’s common in children but non-life threatening.
Dr. Lewis: Henoch-Schonlein Purpura or HSP is a common childhood vasculitis, most commonly occurring in children ages 3 to 15 years of age. The key feature is palpable purpura. The rash is usually below the waist in the legs and buttocks. The child may also have systemic symptoms including abdominal pain, polyarthralgia and signs of renal disease such as hematuria or hypertension. Some children may have a low grade fever2
The rash is often the first sign of HSP* and will last around 1 week. Abdominal pain may occur 1 week before or after the onset of the rash. Platelet counts will be normal. But half of
the cases will have renal complications ranging from asymptomatic microscopic hematuria to acute or chronic renal failure3. HSP is usually self-limiting in 3-4 weeks and management consists usually of symptomatic relief4
. NSAIDs and prednisone may be considered if there
is significant joint involvement and abdominal pain5.
*For details on follow-up, please see Henoch-Schonlein Purpura (IgA Vasculitis) Treatment & Management. Updated: Jan 08, 2021
Author: Rajendra Bhimma, MBChB, MD, PhD, DCH (SA), FCP(Paeds)(SA), MMed(Natal) from emedicine.medscape.com.
Samantha: With HSP, this self-resolving vasculitis is usually not concerning and management is conservative with blood pressure and urinalysis surveillance for renal complications. What other diseases are also less concerning?
Dr. Lewis: Immune thrombocytopenia or ITP is one of the most common causes of thrombocytopenia in kids The most common age groups affected are between the ages of 1-5 years and are otherwise healthy children present who then have sudden onset of petechiae, purpura, or ecchymoses6. ITP commonly present following a recent history of a viral infection Children can also have nosebleeds, bloody stools or heavier menses. ITP may be primary or secondary, but all have low platelet counts. Most children will recover within 3 months of presentation, even without treatment. In the few with severe bleeding such as heavy epistaxis, GI bleeding, or intracranial hemorrhage, they should be admitted into hospital for stabilization and treatment with IVIG or anti-D immunoglobulin, or glucocorticoids. Overall, these children should avoid vigorous physical activity7
Samantha: Why is it important to determine if a child with purpura is febrile?
Dr. Lewis: As a general consideration for a child with fever and a purpuric rash, sepsis must be considered in your differential.
A septic child looks sick and has abnormal vital signs:
fever, tachycardia, tachypnea and in the late stages, hypotension. Your priority is to stabilize the child’s ABC- airway, breathing, and circulation, and if possible, do a full septic work up.
In children, the infection you must rule out is meningococcemia, which is caused by Neisseria meningitides. Affected children are usually younger than 5 years, late adolescent or young adults, but any age group can be affected. Meningococcemia is rapidly
fatal if not treated with empiric antibiotics and supportive therapy. Children initially present with non-specific flu-like symptoms and fever before the signs and symptoms of sepsis
appear8. The petechiae often present on the trunk and extremities, but can be found anywhere on the body, like the mucosal membranes, head, palms, and soles. The centre of
the petechiae may transform into a grey color and then become necrotic. In the severest form, the petechiae become palpable and purulent9. Children with meningococcemia are
often admitted to the PICU because of the severity of their clinical status. They often need significant fluid resuscitation, inotropes and antibiotics. A definitive diagnosis is made via
positive blood and/or CSF cultures; but again, do not delay antibiotics if the patient is unwell and unstable.
Samantha: With meningococcemia being so dangerous, what other infections are a cause for concern for a patient presenting with purpura and fever?
Dr. Lewis: Hemolytic uremic syndrome or HUS which may also present with a fever and purpuric rash. HUS classically presents with the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, and is commonly caused by the ingestion of E. coli 0157H7. Children often present with a one week history of fever, and GI symptoms: often bloody diarrhea accompanied by nausea and vomiting. They may look lethargic, confused, and complain of abdominal pain. Purpura and/or petechiae may be present. These children usually require supportive therapy and antibiotics should be avoided. Meticulous fluid management is required as HUS* can lead to acute kidney injury and renal failure, and even some may require dialysis. Blood transfusions may be necessary for children with severe anemia10,11
*Please see and review Pediatric Hemolytic Uremic Syndrome
Updated: Nov 12, 2018. Author: Robert S Gillespie, MD, MPH from emedicine.medscape.com.