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Petechiae and Ecchymoses 781

Petechiae and Ecchymoses
VetBooks.ir Diseases and Disorders

weakness, collapse), or signs related to an
BASIC INFORMATION
underlying disease process (e.g., signs of with slide review (use peripheral veins in animals
with suspected coagulopathy). If this cannot be
Definition acute kidney injury with leptospirosis, signs done quickly, a blood smear evaluation with
Petechiae and ecchymosis are clinical signs of heat stroke). The clinician should obtain a platelet estimate and packed cell volume/total
rather than a specific disease. thorough history to include current medica- protein (PCV/TP) should be performed.
• Petechiae are pinpoint (1-3 mm) hemorrhages tions, recent vaccinations, access to toxins/drugs, Routine chemistry and (free-catch) urinalysis
that occur due to capillary bleeding and are travel, ectoparasites prophylaxis or exposure, can assess for concurrent disease. Coagulation
specific for defects in primary hemostasis and any history of prolonged or spontaneous profile or specific tests of coagulation may also
(i.e., platelet number/function) or vasculitis. hemorrhage. be helpful. In general, dogs with coagulation
• Ecchymoses are larger (>1 cm) subcutaneous disorders and no other systemic disease (e.g.,
hemorrhages occurring due to arteriole or PHYSICAL EXAM FINDINGS primary IMT, congenital coagulation disorder)
venule bleeding caused by defects in primary Exam should focus on identifying areas of are less ill than dogs with other causes of
or secondary (i.e., coagulation cascade) petechiae (e.g., mucous membranes, inner hemorrhage.
hemostasis. pinnae, nonhaired regions) and ecchymoses
(e.g., ventral abdomen, inguinal region, sites Differential Diagnosis
Synonym of recent venipuncture) and should confirm • Erythema: blanches with pressure (diascopy)
Purpura that they are truly regions of hemorrhage as as opposed to petechiae/ecchymosis
opposed to surface/cutaneous lesions (i.e., skin • Cutaneous hemangiomas or hemangiosarcoma
Epidemiology disease). Petechiae and ecchymoses should NOT • Burns (chemical, thermal)
SPECIES, AGE, SEX blanch with pressure. Careful exam should • Cutaneous drug reaction
• Dogs more than cats look for other evidence of hemorrhage (e.g., • Traumatic dermatitis
• Age varies with cause (e.g., congenital rectal exam for melena and/or hematochezia).
platelet disorders in young animals, immune- Pallor, tachycardia, and a soft systolic heart Initial Database
mediated thrombocytopenia during middle murmur are often recognized with severe • CBC
age, coagulopathy secondary to malignancy anemia. Other findings reflect underlying ○ Rule out thrombocytopenia (manual count
in older animals) disease. if automated is decreased). Microscopic
slide review is important because platelet
GENETICS, BREED PREDISPOSITION Etiology and Pathophysiology clumping (best seen on the feathered
Certain breeds are predisposed to conditions • Thrombocytopenia (<30,000 platelets/mcL) edge) can result in artifactual decrease in
that may result in petechiae or ecchymoses is the most common cause of petechiae and/ count. Spontaneous hemorrhage occurs
(pp. 972 and 1043). or ecchymoses. only if platelet count is < 30,000/mcL
○ Decreased production (e.g., bone marrow unless complicated by thrombocytopathy
CONTAGION AND ZOONOSIS disorders, drugs or toxins, immunologic or vasculitis. Large platelets suggest
Several infectious diseases can cause thrombo- attack on platelet precursors); often part platelet regeneration, as is common in
cytopenia or vasculitis, resulting in petechiae of pancytopenia IMT.
or ecchymosis. Many are vector transmitted ○ Platelet destruction (e.g., primary or ○ Anemia and low TP may reflect severe
rather than directly contagious, and many are secondary immune-mediated thrombocy- hemorrhage.
indirect zoonoses (e.g., Rocky Mountain spotted topenia [IMT], Anaplasma platys infection) ○ Pancytopenia suggests bone marrow
fever, anaplasmosis). ○ Platelet consumption (e.g., disseminated disease.
intravascular coagulation [DIC], vasculitis) ○ Neutrophilia suggests infection or inflam-
RISK FACTORS • Thrombocytopathy (must be severe to result matory disease.
Any cause of thrombocytopenia, thrombocy- in spontaneous hemorrhage) • Platelet estimate (if CBC cannot be per-
topathy, or vasculitis can result in petechiae; ○ Congenital/inherited platelet disorders formed rapidly)
these or any secondary hemostatic defect can (e.g., Glanzmann’s thrombasthenia) ○ Each platelet observed in a high-power
cause ecchymosis. ○ Drugs/toxins (e.g., aspirin, clopidogrel, field (hpf, 1000×) suggests ≈15,000 plate-
nonsteroidal antiinflammatory drugs lets (i.e., average number of platelets/hpf
ASSOCIATED DISORDERS [NSAIDs], colloids) × 15,0000 = platelet estimate per mcL)
Anemia and evidence of bleeding from the ○ Concurrent diseases (e.g., hepatic disease, ○ Normal dogs and cats should have > 10
gastrointestinal (GI) tract, urinary tract, or uremia, rickettsial infections) platelets/hpf, but spontaneous hemorrhage
respiratory tract are often identified. ○ von Willebrand factor deficiency is unlikely due to thrombocytopenia alone
• Vasculitis: rickettsial disease, drug reaction, if > 2 platelets/hpf
Clinical Presentation immune-mediated vasculitis • Chemistry panel: ± increased blood urea
DISEASE FORMS/SUBTYPES • Secondary hemostatic defects (e.g., vitamin nitrogen (BUN) if GI bleeding, ± hypo-
Petechiae and ecchymosis can occur as a sign K rodenticide toxicosis) can cause ecchymosis proteinemia from blood loss, ± hyperglobu-
of an underlying coagulation disorder or as a but not petechiae linemia from infection/inflammation
complication of systemic disease. • Often, multiple mechanisms contribute to • Urinalysis (free-catch sample): ± hematuria,
signs simultaneously. ± proteinuria
HISTORY, CHIEF COMPLAINT • Coagulation panel (prothrombin time/ acti-
Rarely are patients presented due to owner DIAGNOSIS vated partial thromboplastin time [PT/aPTT]
observation of petechiae and/or ecchymoses. [p. 1325]): not required if thrombocytopenia
More commonly, they are presented for signs Diagnostic Overview confirmed unless DIC suspected; useful to
related to bleeding (e.g., epistaxis, hyphema, History and exam guide diagnostic evaluation, assess secondary hemostasis for ecchymotic
hematuria), signs related to anemia (e.g., but the most important initial test is a CBC hemorrhage

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