Version May 2024
INTRODUCTION — This review will discuss the causes of purpuric skin lesions in children. The evaluation of purpuric skin lesions, bleeding in children, and sepsis (a major consideration for children with fever, petechiae, and/or purpura) are discussed separately:
●(See "Purpuric skin lesions (petechiae, purpura, and ecchymoses) in children: Evaluation".)
●(See "Approach to the child with bleeding symptoms".)
●(See "Sepsis in children: Definitions, epidemiology, clinical manifestations, and diagnosis" and "Septic shock in children in resource-abundant settings: Ongoing management after resuscitation".)
TERMINOLOGY — Purpuric skin lesions include (see "Approach to the clinical dermatologic diagnosis"):
●Petechiae – Petechiae are nonblanching red to purple macules that are pinpoint to 1 to 2 mm in size and are not raised (picture 1). Lack of blanching is often best appreciated by diascopy which involves the use of a clear glass slide or drinking glass to apply pressure to the skin. They arise from bleeding into the skin from small capillaries.
Infection and thrombocytopenia are important causes of petechiae, although they may arise in other conditions.
●Purpura – Purpura are hemorrhagic lesions that are larger than petechiae and result from bleeding within the skin or mucous membranes from capillaries and other small blood vessels. Purpura can appear as nonblanchable dark red to dark purple macules, papules, patches, or plaques (picture 2A-B and picture 3 and picture 4). In some cases, purpura may be tender or painful. Purpuric papules are also called palpable purpura and indicate small vessel vasculitis.
Purpura occur in patients with infection, systemic vasculitis, thrombocytopenia, or coagulation disorders.
●Ecchymoses (bruises) – Ecchymoses reflect larger extravasations of blood arising from a hematoma or larger confluent purpura (picture 5). In addition to direct trauma, they can be associated with coagulation disorders and severe thrombocytopenia.
Skin color can influence the appearance of purpuric skin lesions; darker skin pigmentation can reduce the visibility of purpura (picture 2A-B).
PATHOPHYSIOLOGY — Purpuric skin lesions may result from disruptions in vascular integrity (eg, infection, vasculitis, collagen disorders, trauma), abnormalities in primary or secondary hemostasis (thrombocytopenia, abnormal platelet function, clotting factor deficiency, or abnormal clotting factor function), or both (eg, disseminated intravascular coagulation caused by sepsis) [1,2].
Careful evaluation of any child with petechiae and purpura is important to facilitate timely diagnosis and treatment, particularly in children who are ill-appearing. The type, location, and extent of the lesions, along with the overall appearance of the child, will help guide the initial evaluation and suggest the underlying cause. In children with fever and purpuric skin lesions, especially petechiae and/or purpura, serious infection with sepsis and disseminated intravascular coagulation require rapid recognition and treatment. (See "Purpuric skin lesions (petechiae, purpura, and ecchymoses) in children: Evaluation".)
CAUSES
Disruptions in vascular integrity
Trauma — Trauma is a common etiology of purpura (especially ecchymoses and sometimes petechiae) in children. Evaluation of children with bruises or localized traumatic petechiae must distinguish lesions caused by unintentional trauma from child abuse:
●Unintentional trauma – Bruises from unintentional trauma vary in size from a few millimeters to several centimeters and are frequently located over extensor surfaces of the lower legs, bony prominences including the knees and elbows, and the forehead. Petechiae caused by trauma may be adjacent to bruises or may occur in isolation at sites of trauma.
●Child abuse – The age of the child and the nature, shape, location, distribution, number, and size of bruises may each raise suspicion for abuse (see "Physical child abuse: Recognition", section on 'Inflicted bruises'):
•Any bruising in infants younger than 6 months of age
•More than one bruise in a pre-mobile infant and more than two bruises in a crawling child
•Bruises located on the torso, buttocks, ear, neck, angle of the jaw, fleshy cheek or eyelid
•Subconjunctival hemorrhages
•Bruises with a pattern of the striking object (figure 1) (eg, slap, belt, or loop marks (picture 6); spoons; spatulas; or other objects)
•Bruises with other previously reported, abuse-associated pattern
•Human bite marks
Bruising is the most common presenting feature of physical abuse in children. Other types and patterns of injury that raise suspicion for child abuse are listed in the table and discussed separately (table 1). (See "Physical child abuse: Recognition".)
Increased venous pressure (mechanical disruption) — Abrupt increase in venous pressure from frequent, forceful coughing, crying, or vomiting can cause petechiae above the nipple line (superior vena cava distribution) through mechanical disruption of small vessels [2]. Petechiae can also develop at the site of tourniquet placement or other localized constrictions in patients with normal hemostasis.
Infection — In the ill-appearing, febrile child, rapidly spreading petechiae and/or purpura point to an underlying life-threatening infection. Bacterial etiologies include Neisseria meningitidis (meningococcemia), Streptococcus pneumoniae, and Group A Streptococcus. These patients require emergency stabilization and treatment for sepsis and septic shock (algorithm 1). (See "Septic shock in children in resource-abundant settings: Rapid recognition and initial resuscitation (first hour)".)
Patients with sepsis and DIC may develop purpura fulminans (PF) with microvascular thrombosis, skin infarction, and hemorrhage. Clinically, these patients are ill-appearing and have fever, hypotension, and bleeding. The skin lesions of PF have a characteristic appearance, which helps to distinguish them from other purpuric lesions (picture 3). Erythema is followed by central areas of blue or black hemorrhagic necrosis with a surrounding erythematous border. The lesions are painful and indurated. (See "Clinical manifestations of meningococcal infection", section on 'Purpura fulminans' and "Disseminated intravascular coagulation in infants and children".)
Children with infective endocarditis may rarely display isolated or clustered petechiae from septic emboli in the distal extremities as well as in the subconjunctiva (picture 7 and picture 8). (See "Infective endocarditis in children", section on 'Clinical manifestations'.)
Viral infections that may present with fever and petechiae include:
●Parvovirus (picture 9 and picture 10) (see "Clinical manifestations and diagnosis of parvovirus B19 infection")
●Enterovirus (hand, foot, and mouth disease) (see "Hand, foot, and mouth disease and herpangina")
●Dengue virus (picture 11) (see "Dengue virus infection: Clinical manifestations and diagnosis")
●Ebola virus (purpura may also develop) (See "Clinical manifestations and diagnosis of Ebola virus disease".)
●Marburg virus (purpura may also develop)_ (See "Marburg virus", section on 'Clinical manifestations'.)
●Epstein-Barr virus (See "Clinical manifestations and treatment of Epstein-Barr virus infection", section on 'Other manifestations'.)
●Cytomegalovirus (See "Overview of cytomegalovirus infections in children", section on 'Clinical manifestations'.)
In addition, Rocky Mountain spotted fever and other Rickettsial infections such as Japanese spotted fever, Mediterranean spotted fever, and Siberian tick typhus commonly present with petechiae. Petechiae have also been described in children with Ehrlichiosis. (See "Clinical manifestations and diagnosis of Rocky Mountain spotted fever" and "Other spotted fever group rickettsial infections" and "Human ehrlichiosis and anaplasmosis", section on 'Children'.)
Crimean-Congo hemorrhagic fever virus is transmitted via tick bite and, in severe cases causes petechiae, ecchymoses, along with serious bleeding. (See "Crimean-Congo hemorrhagic fever", section on 'Clinical manifestations'.)
Immunoglobulin A vasculitis (IgAV; Henoch-Schönlein purpura [HSP]) — IgAV (HSP) is the most common cause of vasculitis in children, occurring at a mean age of six years [2,3]. The patient may be uncomfortable and refuse to walk. Palpable purpura with or without petechiae is an essential finding for the diagnosis of IgAV (HSP) (picture 12 and picture 2A and picture 13). The purpura tend to be concentrated in dependent areas such as the buttocks and lower extremities. The face, trunk, and upper extremities may be involved in nonambulatory children. Other clinical manifestations include periorbital and pedal edema, arthritis (commonly of the knees and ankles), abdominal pain with or without gastrointestinal bleeding, scrotal swelling, and nephritis. A normal platelet count and coagulation studies distinguishes IgAV from other causes of vasculitis including infection, Kawasaki disease, infection, leukemia, lymphoma, and rheumatologic disorders. (See "IgA vasculitis (Henoch-Schönlein purpura): Clinical manifestations and diagnosis" and "Vasculitis in children: Evaluation overview".)
Drug-induced vasculitis — Numerous drugs have been associated with vasculitis and purpura. These include sulfonamides, penicillins, and phenytoin [4]. Drug-induced vasculitis usually develops within 7 to 21 days of starting the drug and may be confined to the skin.
Vitamin C deficiency — Dietary deficiency of Vitamin C (scurvy) is relatively rare in developed countries. It may occur in individuals with severely restricted diets (anorexia, neurodevelopmental delay, and/or hyperalimentation without vitamin C supplementation). Vitamin C deficiency results in impaired collagen synthesis.
The typical pathologic manifestations of vitamin C deficiency are noted in collagen-containing tissues and in organs and tissues such as skin, cartilage, dentin, osteoid, and capillary blood vessels. Scurvy may present with gum bleeding, petechiae or ecchymoses. In addition, the prominence of hair follicles on the thighs and buttocks and the eruption of coiled, fragmented hair with a characteristic corkscrew appearance are specific features of vitamin C deficiency. Petechiae found on the skin have a characteristic pale halo ring around a central erythematous core (picture 14). These lesions heal rapidly after the administration of vitamin C. (See "Overview of water-soluble vitamins", section on 'Vitamin C (ascorbic acid)'.)
Ehlers-Danlos syndrome — Ehlers-Danlos syndrome (EDS) is the name given to a group of inherited disorders that involve genetic defects in collagen and connective-tissue synthesis and structure. This heterogeneous group is characterized by joint hypermobility, cutaneous fragility, and hyperextensibility. Fragility of dermal skin is common, with frequent bruises and delayed wound healing. In some cases, abnormal blood vessel structure causes capillary hemorrhage.
Pigmented purpuric dermatoses (PPDs) — The PPDs, also known as capillaritis, purpura simplex, and inflammatory purpura without vasculitis, are a group of chronic, benign, cutaneous eruptions characterized by the presence of petechiae, purpura, and yellow to brown pigmented patches caused by hemosiderin deposition within the dermis (picture 15 and picture 16). PPDs most commonly occur on the lower extremities and may be asymptomatic or pruritic. PPD is not painful and is not associated with bleeding or systemic illness . The diagnosis is usually made through clinical inspection and the recognition of classic clinical features. A skin biopsy is useful when the diagnosis remains uncertain following clinical examination. Biopsies may help to distinguish PPD from disorders in the differential diagnosis, such as cutaneous vasculitis. There are several different subtypes of PPD, although Schamberg disease (picture 17) is the most common. (See "Pigmented purpuric dermatoses (capillaritis)".)
Disorders of hemostasis
Thrombocytopenia — Conditions that result in decreased platelet number may present with purpuric skin lesions. The normal platelet count is >150,000/mm3. These conditions may be inherited or acquired, although acquired thrombocytopenia is more common. In general, patients do not develop bleeding until the platelet count drops below 20,000/mm3, unless there is associated trauma or surgery.
Thrombocytopenia may be a result of increased platelet destruction, decreased platelet production, or sequestration (table 2). Several of the most important causes of purpura due to thrombocytopenia are provided below. As highlighted above, a child who is febrile and ill appearing with purpura and thrombocytopenia should be presumed to have a life-threatening infection and should be treated for sepsis. The approach to unexplained thrombocytopenia and causes of thrombocytopenia in children are discussed in detail separately. (See "Approach to the child with bleeding symptoms" and "Causes of thrombocytopenia in children".)
Immune thrombocytopenia (ITP) — ITP is one of the most common causes of petechiae and purpura in children [2]. This immune-mediated disorder is characterized by the sudden development of petechiae (picture 18) and ecchymoses (picture 19) in an otherwise healthy child, although symptoms may occasionally develop more gradually. Epistaxis occurs in 10 to 20 percent. More serious bleeding may occur but is uncommon. ITP occurs most frequently in children between the ages of one to five years, but also can present in older children and adults. In young children, the development of ITP is often preceded by a mild viral illness. The diagnosis of ITP is based upon two clinical features (see "Immune thrombocytopenia (ITP) in children: Clinical features and diagnosis"):
●Isolated thrombocytopenia, with otherwise normal blood counts and peripheral blood smear
●No clinically apparent associated conditions that may cause thrombocytopenia
Hemolytic uremic syndrome (HUS) — HUS is a disease that primarily affects young children and is characterized by the triad of thrombocytopenia, microangiopathic anemia, and acute kidney injury. Patients may rarely manifest purpura. HUS can be divided into two forms based upon clinical presentation: Typical HUS is most common and usually follows a prodromal infectious disease, most commonly diarrhea, and less frequently an upper respiratory infection. This syndrome is classically associated with Escherichia coli serotype O157:H7 (see "Clinical manifestations and diagnosis of Shiga toxin-producing Escherichia coli (STEC) hemolytic uremic syndrome in children", section on 'Thrombocytopenia'). Atypical HUS is a heterogeneous disorder characterized by the absence of diarrhea. (See "Complement-mediated hemolytic uremic syndrome in children".)
Thrombotic thrombocytopenic purpura (TTP) — TTP is most common in adults but is occasionally seen in children. The classic pentad includes thrombocytopenia, microangiopathic hemolytic anemia, fever, renal dysfunction, and neurologic abnormalities. It is a usually a result of deficiency of the ADAMTS-13 protease, which is responsible for cleaving von Willebrand factor (VWF) multimers. Without this cleavage, ultra large VWF multimers circulate, stimulating microvascular platelet thrombi which cause microangiopathic hemolytic anemia and thrombocytopenia. TTP is most often a result of antibody mediated destruction of ADAMTS-13. However, a rare autosomal recessive inherited deficiency of ADAMTS-13 can cause TTP in young children. (See "Diagnosis of immune TTP" and "Hereditary thrombotic thrombocytopenic purpura (hTTP)".)
Disseminated intravascular coagulation (DIC) — Thrombocytopenia may be an early manifestation of disseminated intravascular coagulation. (See "Disseminated intravascular coagulation in infants and children".)
Bone marrow infiltration (malignancy) — Diseases associated with decreased amounts of functional bone marrow also may present with thrombocytopenia and purpura [2]. Most notable in this group in children are acute leukemia and neuroblastoma. In the majority of cases, hematologic abnormalities other than thrombocytopenia are also present (eg, anemia, leukopenia, or leukocytosis), but occasionally a decrease in the platelet count may be the only abnormality. (See "Overview of the clinical presentation and diagnosis of acute lymphoblastic leukemia/lymphoma in children", section on 'Laboratory studies' and "Clinical presentation, diagnosis, and staging evaluation of neuroblastoma".)
Neonatal alloimmune thrombocytopenia — Neonatal alloimmune thrombocytopenia (NAIT) occurs when fetal platelets contain an antigen inherited from the father that the mother lacks. The mother forms IgG class antiplatelet antibodies against the "foreign" antigen; these cross the placenta and destroy fetal platelets, resulting in fetal and neonatal thrombocytopenia. Plasma levels of thrombopoietin in these patients are normal because the megakaryocytes and platelets that are produced bind to this growth factor. In contrast to Rh sensitization, NAIT often develops in the first pregnancy of an at-risk couple.
NAIT can result in severe thrombocytopenia in the fetus because platelet antigens form early in gestation and maternal antibodies cross the placenta in early midtrimester. The most serious complication is intracranial hemorrhage, which occurs in approximately 10 to 20 percent of affected newborns; one-quarter to one-half of these occur in utero. The risk of severe thrombocytopenia and intracranial hemorrhage is greater in alloimmune than in autoimmune thrombocytopenia. (See "Neonatal thrombocytopenia: Etiology".)
Inherited thrombocytopenias — True hereditary isolated thrombocytopenia is an extremely rare cause of bleeding. (See "Neonatal thrombocytopenia: Etiology", section on 'Genetic disorders' and "Causes of thrombocytopenia in children", section on 'Inherited platelet disorders'.):
●Congenital amegakaryocytic thrombocytopenia is characterized by severe thrombocytopenia that is present at birth and may be associated with skeletal abnormalities.
●The thrombocytopenia with absent radii (TAR) syndrome has an autosomal recessive inheritance. The thrombocytopenia in TAR is variable in severity but tends to improve over time.
●Wiskott-Aldrich syndrome is an X-linked recessive disorder characterized by thrombocytopenia, eczema, and immunodeficiency. Infants with Wiskott-Aldrich may present with thrombocytopenic purpura beginning in the newborn period. Shortened platelet survival in this disease comes from an intrinsic platelet abnormality.
●Patients with inherited giant-platelets may have Bernard-Soulier syndrome or one of the MYH-9 related syndromes (May-Hegglin anomaly, Sebastian, Fechtner, or Epstein). The MYH-9 related disorders may be associated with sensorineural hearing loss, glomerulonephritis and cataracts. The bleeding phenotype is variable.
Drug-induced thrombocytopenia — Numerous drugs have been reported to cause thrombocytopenia due to the formation of antibodies directed against platelets with resultant increased platelet destruction. The drugs causing immune-mediated thrombocytopenia that are most commonly used in children include sulfa compounds (eg, trimethoprim-sulfamethoxazole), valproic acid, and phenytoin. (See "Drug-induced immune thrombocytopenia".)
Alternatively, drugs may also cause thrombocytopenia as a result of decreased platelet production. Any drug capable of causing general bone marrow suppression can produce thrombocytopenia (eg, carbamazepine, chloramphenicol). Valproic acid causes dose-related suppression of platelet production in addition to sporadic, immune-mediated platelet destruction. (See "Treatment of acquired aplastic anemia in children and adolescents".)
Bone marrow failure — Aplastic anemia (AA) is a rare disorder of hematopoiesis characterized by pancytopenia and bone marrow hypoplasia. The majority of cases are acquired, and this appears to be an immune mediated condition. In some patients with the acquired form, AA is preceded by hepatitis, viral infection, or toxin exposure; though there is no identifiable etiologic agent in the majority. Patients with one of the rare, congenital bone marrow failure syndromes (Fanconi anemia, dyskeratosis congenital, cartilage-hair hypoplasia) often have other abnormalities on physical exam. (See "Treatment of acquired aplastic anemia in children and adolescents", section on 'Classification of severity' and "Aplastic anemia: Pathogenesis, clinical manifestations, and diagnosis".)
Sequestration — Splenomegaly that comes from numerous causes (eg, portal hypertension, storage diseases) can result in sequestration of platelets and thrombocytopenia. The spleen is markedly enlarged and very firm in these disorders. Purpura that comes from platelet sequestration alone is rare because the platelet count usually does not fall below 40,000/mm3. Bleeding may occur, however, when the platelet sequestration is associated with liver disease and clotting abnormalities. Platelet sequestration and consumption also can occur in large hemangiomas (Kasabach Merritt syndrome).
Platelet function abnormalities — Platelet function disorders may be acquired or inherited; acquired platelet function abnormalities are much more common:
●Acquired – Drugs are the most common cause of acquired platelet dysfunction. Aspirin is the best known of the drugs that cause platelet dysfunction. A single dose of aspirin can irreversibly alter platelet function by blocking the normal pathway of thromboxane-induced platelet aggregation. Nonsteroidal antiinflammatory drugs (NSAIDs), such as ibuprofen, have a similar mechanism of action, but the effects are reversible, and the disruption of platelet function is less pronounced. Platelet dysfunction also has been associated with antihistamines, serotonin-specific reuptake inhibitors, beta-lactam antibiotics, phenothiazines, valproic acid, and guaifenesin. Myeloproliferative and myelodysplastic syndromes and uremia are other important acquired causes of platelet dysfunction in children. Patients with uremia often develop platelet function abnormalities that may result in purpura (see "Uremic platelet dysfunction"). A more extensive discussion of acquired platelet function abnormalities in children is provided separately. (See "Inherited platelet function disorders (IPFDs)".)
●Inherited – Inherited platelet function disorders are an uncommon cause of bleeding. There are several disorders which range in severity. The most severe, but also quite rare, are Glanzmann thrombasthenia and Bernard-Soulier syndrome.
In Glanzmann thrombasthenia, the platelet count is normal and there is a deficiency of the glycoprotein IIb/IIIa complex. Bernard-Soulier syndrome results from a deficiency of platelet glycoprotein protein complex GPIb/IX/V, which mediates the initial interaction of platelets to the subendothelial components via the von Willebrand protein. In Bernard-Soulier syndrome the platelet count may be decreased, but, characteristically, the platelets are large, often the size of red blood cells, and may be missed because most automatic counters do not count them as platelets. Both Bernard-Soulier syndrome and Glanzmann thrombasthenia are characterized by life-long bleeding.
Other more common, but less severe, platelet function abnormalities include storage pool defects (eg, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome) or mild secretion defects. (See "Inherited platelet function disorders (IPFDs)".)
Clotting factor deficiencies — Purpura can be the presenting symptom of a congenital or acquired deficiency of coagulation factors. The most commonly encountered congenital deficiencies are von Willebrand disease, hemophilia A (factor VIII deficiency), and hemophilia B (factor IX deficiency). Although the latter two disorders have an X-linked recessive mode of inheritance, the de novo appearance of coagulopathy is not uncommon, particularly in children with severe hemophilia A (factor VIII activity less than 1 percent). Therefore, a family history of affected males may be helpful in establishing the diagnosis of hemophilia, but the absence of such a history does not eliminate this diagnostic possibility.
Von Willebrand disease (VWD) — VWD is the most common congenital bleeding disorder, present in approximately 1 percent of the population. It is actually a collection of disorders characterized by either quantitative or qualitative abnormalities of von Willebrand factor (vWf). VWD affects males and females equally and is generally inherited as an autosomal dominant trait with variable penetrance. VWD should be suspected in patients with a history of easy bruising, mucous membrane bleeding (epistaxis, heavy menstrual bleeding), or prolonged bleeding after a surgical procedure (eg, post-tooth extraction). In contrast to hemophilia, joint and muscle bleeds are very uncommon in VWD. (See "Clinical presentation and diagnosis of von Willebrand disease".)
Hemophilia — Hemophilia, the most common inherited severe bleeding disorder, is an X-linked disorder that affects males of all ethnic groups. Hemophilia A (deficiency of factor VIII) occurs in approximately 1 in 5000 live male births and is five to six times more common than Hemophilia B (deficiency of factor IX). The severity of hemophilia is classified according to the amount of circulating functional clotting factor:
●Less than 1 percent – Severe disease
●1 to 5 percent – Moderate disease
●Greater than 5 percent – Mild disease
Patients with severe hemophilia experience frequent spontaneous bleeding episodes, in contrast to those with moderate or mild hemophilia in whom trauma or surgery is usually required to provoke hemorrhage. Although bleeding can occur in almost any site, hemarthrosis (intra-articular bleeding) is the most common clinical manifestation, and the ankles, knees, and elbows are most frequently affected.
Children with hemophilia often come to medical attention when they develop purpura either spontaneously or after mild trauma. The ecchymoses in boys with hemophilia are often quite pronounced and palpable for the degree of trauma. The diagnosis of hemophilia should also be entertained in newborns who develop excessive bleeding after circumcision and in infants with prolonged bleeding from lacerations of the lip, tongue, or frenulum. Prompt recognition of the disorder at this early age allows for careful surveillance, appropriate treatment, and early genetic counseling for parents. (See "Clinical manifestations and diagnosis of hemophilia".)
Neonatal purpura fulminans — Neonatal purpura fulminans usually occurs on the first day of life and is caused by congenital severe deficiency of protein C or protein S. Affected infants present with ecchymoses, extensive venous and arterial thromboses, laboratory evidence of disseminated intravascular coagulation, and extremely low levels of protein C antigen (less than 1 percent of normal).
Administration of exogenous protein replacement (Protein C concentrate or fresh frozen plasma) appears to be critical for the treatment of neonatal purpura fulminans, while heparin and antiplatelet agents are ineffective. (See "Protein C deficiency", section on 'Neonatal purpura fulminans'.)
Severe acquired deficiency of the anticoagulant proteins, protein C and protein S, may also present with non-infectious purpura fulminans or in association with infectious disseminated intravascular coagulopathy. (See 'Infection' above.)
Other congenital factor deficiencies — While VWD and hemophilia A and B represent the majority of inherited bleeding disorders, hereditary deficiencies of other clotting factors may also be encountered. Deficiencies of the following factors result in clinical bleeding: II, V, X, VII, XI, XIII, and fibrinogen. These are all autosomal traits and are usually symptomatic only in patients with homozygous deficiencies. Most patients with the above deficiencies will have an abnormal PT or aPTT. The diagnosis requires specific factor assays. Patients with factor XIII deficiency will have normal screening tests and can be diagnosed with a factor XIII functional assay that assays clot solubility. (See "Rare inherited coagulation disorders".)
Vitamin K deficiency — Vitamin K is an essential fat-soluble vitamin that is required for the post-translational gamma-carboxylation of several of the clotting factors. The clotting factors that are vitamin K dependent are: II, VII, IX, and X. Deficiency of vitamin K leads to low levels of these clotting factors which may present with purpura or more systemic bleeding. (See "Overview of vitamin K", section on 'Vitamin K deficiency'.)
Hemorrhagic disease of the newborn, with clinical manifestations that range from purpura to intracranial hemorrhage, may occur in infants who do not receive prophylactic vitamin K at birth. This important step in normal newborn care may be overlooked when infants are born at home, or when problems develop in the delivery room and vitamin K is not given. The classic form presents in the first week of life, and the late form presents between two weeks and six months of life. The deficiency is the result of inadequate stores of vitamin K due to maternal deficiency or exclusive breastfeeding. (See "Overview of vitamin K", section on 'Vitamin K-deficient bleeding in newborns and young infants'.)
Vitamin K deficiency may occur in older children with malabsorption or chronic diarrhea. Ingestion of warfarin or long-acting superwarfarin rat poisons (eg, brodifacoum), which interferes with the metabolism of vitamin K, may also present with purpura.
Liver disease — The majority of clotting factors are produced in the liver. As a result, impaired hepatic synthesis, due to either inherited or acquired liver dysfunction may lead to a coagulopathy and purpura.
Disseminated intravascular coagulation (DIC) — DIC is a complex consumptive coagulopathy that is characterized by diffuse intravascular activation of coagulation resulting in thrombocytopenia and clotting factor deficiencies. It is associated with a variety of infectious and noninfectious disease states (table 3).
Thrombocytopenia from shortened platelet survival may occur due to fibrin deposition and platelet consumption. In addition, the intravascular consumption of clotting factors may cause purpura because of factor depletion and, in severe cases, may lead to widespread, rapidly progressing purpuric lesions (purpura fulminans) associated with thrombosis or emboli.
Infections are the most common cause of DIC in children (table 3). Although other signs of serious illness are usually present in the child with purpura caused by DIC, fever, petechiae alone or in combination with purpura may be the only significant findings in the early stages of severe bacterial infections such as meningococcemia. Further investigations and appropriate therapy should proceed rapidly in such instances. (See 'Infection' above.)
SUMMARY AND RECOMMENDATIONS
●Terminology – Purpuric skin lesions include (See 'Terminology' above.):
•Petechiae – Petechiae are pinpoint 1 to 2 mm nonblanching red to purple macules on the skin (picture 1).
•Purpura – Purpura are larger, nonblanchable dark red to dark purple macules, papules, patches, or plaques that may occur on the skin or mucous membranes (picture 2A-B and picture 3 and picture 4).
•Ecchymoses (bruises) – Ecchymoses reflect larger extravasations of blood (hematoma or confluent purpura) (picture 5).
Darker skin pigmentation can reduce the visibility of purpuric skin lesions. For petechiae and purpura, lack of blanching is often best appreciated by diascopy (use of a clear glass slide or drinking glass to apply pressure to the skin).
●Causes – The causes of purpuric skin lesions in children can be broadly categorized as follows:
•Disruption in vascular integrity (see 'Disruptions in vascular integrity' above)
•Disorders of hemostasis from:
-Thrombocytopenia (see 'Thrombocytopenia' above)
-Platelet function disorders (see 'Platelet function abnormalities' above)
-Clotting factor deficiencies (see 'Clotting factor deficiencies' above)
-Disseminated intravascular coagulation (See 'Disseminated intravascular coagulation (DIC)' above.)
The type of skin lesion can provide clues to the underlying cause (see "Purpuric skin lesions (petechiae, purpura, and ecchymoses) in children: Evaluation", section on 'Terminology'):
•Petechiae – Infection and thrombocytopenia are important causes of petechiae, although they may arise in other conditions.
•Purpura – Purpura can occur in patients with infection, systemic vasculitis, thrombocytopenia, or coagulation disorders
•Ecchymoses (bruises) – In children, ecchymoses are often caused by direct trauma. However, they are also associated with coagulation disorders, specifically factor deficiencies, and severe thrombocytopenia.
●Careful evaluation of any child with petechiae and purpura is important to facilitate timely diagnosis and treatment, particularly in children who are ill-appearing. The type, location, and extent of the lesions, along with the overall appearance of the child, will help guide the initial evaluation and suggest the underlying cause. In children with fever and purpuric skin lesions, especially petechiae and/or purpura, serious infection with sepsis and disseminated intravascular coagulation require rapid recognition and treatment. (See "Purpuric skin lesions (petechiae, purpura, and ecchymoses) in children: Evaluation".)
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