Clinical Pearls

When parent claim their child had 'hives’ they are often wrong.  We suggest that if you did not review pictures of the rash, you instead review these photos and questions below to determine if these were truly hives, or a macular papular rash (which is far more common).

The vast majority of urticaria, angioedema, and maculopapular rashes that children experience while on antibiotics are NOT caused by antibiotics, but instead by the underlying infection that antibiotics were prescribed for and the immune response to it.

A wheal (hives) in patients with urticaria has three typical features:

• central swelling of variable size, almost invariably surrounded by reflex erythema
• an itching or sometimes burning sensation
• fleeting nature, with the skin returning to its normal appearance usually within 30 minutes to 24 h*.

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In contrast, a maculopapular rash usually has the following characteristics:

• Lasts more than 24 hours
• Scale, or dry skin
• Does not come or go, nor move around.  It starts in a spot (may spread) worsens then fades.
• Flat, red area on the skin that is covered with small confluent bumps. (It may only appear red in lighter-skinned people)

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