Approach to the Problem
The child who presents with a nonblanching rash requires careful evaluation. Purpuric lesions, including petechiae and ecchymoses, usually result from vascular injury or disorders of hemostasis. The underlying etiology may be trauma, a simple viral infection, or a more serious condition such as leukemia or a bleeding disorder. When a nonblanching rash is seen in association with fever, serious bacterial infection, including meningococcemia, must be considered.
Key Points in the History
• A history of fever makes an infectious etiology more likely.
• Acute presentation of a nonblanching rash is more concerning than a rash that has been present for more than a couple of weeks.
• The location and pattern of spread may give a clue to the diagnosis: Rocky Mountain spotted fever (RMSF) tends to begin peripherally; Henoch–Schönlein purpura tends to primarily involve the lower extremities and buttocks.
• The presence of photophobia, headache, or both, in association with a nonblanching rash, raises the suspicion for meningococcal or other bacterial meningitis.
• A history of trauma may be the cause of the nonblanching lesions: localized bruising may follow blunt trauma, and petechiae may be seen in areas of friction or scratching.
• Significant ecchymotic lesions in the absence of a history of trauma should raise suspicion for child physical abuse or a bleeding disorder.
• Forceful coughing or vomiting may cause petechiae, particularly on the face and upper chest.
• Accompanying fatigue may be caused by anemia because of bone marrow suppression or infiltration as seen with leukemia.
• A history of tick bites or travel or activities associated with tick exposure should raise suspicion for RMSF or ehrlichiosis.
• Mongolian spots are present at birth and, though they may fade, they generally do not undergo color changes over time. In contrast, ecchymoses change color over time and eventually resolve.
• A history of easy bruising or excessive bleeding in the patient, or a family history of a bleeding disorder, should raise suspicion for hemophilia or von Willebrand disease.
• Familiarity with home remedies found in certain Asian cultures, such as coining and cupping, is essential.
Key Points in the Physical Examination
• Petechiae are nonblanching macules up to 2 mm in diameter caused by the extravasation of blood from capillaries. Mucosal bleeding sometimes is referred to as “wet purpura.”
• Forceful coughing or vomiting may cause petechiae on the face and chest, above the nipple line.
• Purpura, seen with inflammatory injury to the smaller blood vessels, are elevated, firm, hemorrhagic plaques located predominantly on dependent surfaces.
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