Childhood rashes are cutaneous eruptions of acute onset. Clinically they may be categorized as maculopapular, pustular, vesiculobullous, diffuse/erythematous, or petechial/purpuric in nature. However, in many etiologies these forms may coexist or evolve from one form to another.
Initial considerations in evaluating a rash in children include the morphology, duration, and distribution. Age, gender, family history, medications, known allergies, and exposures are also of primary importance.
Generally, rash in the absence of fever or systemic symptoms is not urgent. When fever or signs of illness are present, urgent evaluation and treatment must be considered. The differential diagnosis is extensive, ranging from self-limiting conditions (e.g., roseola) to life-threatening illnesses such as meningococcal septicemia.
Several systemic conditions with a serious clinical course may have a rash as a component and should be evaluated urgently if suspected.
Macule: a flat skin lesion <1 cm in greatest diameter. When a macular lesion extends beyond 1 cm, the appropriate term is a patch.
Papule: a raised bump <1 cm in diameter. When papular lesions are >1 cm in size, the appropriate term is a plaque (palpable lesions elevated above the skin surface) or a nodule (a larger, firm papule with a significant vertical dimension).
Pustule: a raised blister containing purulent fluid.
Vesicle: a papule containing clear serous fluid.
Bulla: a larger vesicle >1 cm.
Urticaria: a wheal or hive.
Morbilliform eruption: rash that resembles that of measles.
Petechiae: small hemorrhages of skin capillaries.
Purpura: larger areas of bleeding into the skin.
Erythema marginatum: a fleeting pink rash typically involving the trunk and proximal extremities.
Erythema nodosum: a hypersensitivity reaction involving the subcutaneous fat, presenting as red, tender nodules most commonly over shins, calves, and buttocks.
Target lesions: annular erythematous rings with an outer erythematous zone and central blistering sandwiching a zone of normal skin tone.
Targetoid lesions: similar to target lesions but without central blistering.
Professor of Pediatrics
Indiana University School of Medicine
Riley Hospital for Children
PT declares that her spouse owns stocks in Eli Lilly and Company.
Clinical Professor of Dermatology
Columbia University College of Physicians and Surgeons
New York City
NS declares that she has no competing interests.
Professor in Pediatrics
Department of Pediatrics
National University Hospital
HVB declares that he has no competing interests.
Associate Professor of Pediatrics
West Virginia University School of Medicine
LN is an author of a reference cited in this monograph.
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