The patient with an acute maculopapular rash presents a diagnostic challenge to the clinician. The term "maculopapular" is nonspecific, as many eruptions have a primary morphology of macules or papules, and the term may be misused to indicate any rash. The term "rash" is also nonspecific and is sometimes incorrectly applied to any skin finding; eruption may be preferred for a cutaneous reaction of acute onset. However, the term "maculopapular rash" is in common clinical use and will be retained here for simplicity. Synonyms for maculopapular rash include exanthematous eruption (exanthem) and morbilliform eruption.
The term maculopapular rash typically implies an acute and generalized eruption.
Macule: a flat skin lesion ≤1 cm in greatest diameter. When macules are >1 cm, the appropriate term is patch.
Papule: a raised bump ≤1 cm in diameter. When papules are >1 cm in size, the appropriate term is plaque (palpable lesions elevated above the skin surface) or nodule (a larger, firm papule with a significant vertical dimension).
Other morphologic terms encountered in this clinical setting include:
Pustule: a papule containing purulent fluid
Vesicle: a papule containing clear serous fluid
Bulla: a larger vesicle >1 cm
Urticaria: a wheal or hive.
The term maculopapular rash, therefor,e implies a skin eruption of flat and raised lesions.
Professor & Director of Pediatric Dermatology
Department of Dermatology and Pediatrics
UTHealth McGovern Medical School Houston
AAH declares that she has no competing interests
Clinical Research Fellow
Department of Dermatology
University of Texas Health Sciences Center in Houston
QN declares that she has no competing interests.
Dr Adelaide A. Hebert and Dr Quoc-Bao Nguyen would like to gratefully acknowledge Dr Mary DarConte, Dr Mark Naftanel, and Dr Hobart W. Walling, previous contributors to this topic.
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