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, circumscribed skin lesion ≤1 cm in greatest diameter. When macules are >1 cm, the appropriate term is patch.
Papule: an elevated, circumscribed skin lesion ≤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, therefore, implies a skin eruption of flat and raised lesions.
- Allergy to food or drug
- Insect bites or stings
- Adverse drug reaction (e.g., to antibiotic, anticonvulsant, or allopurinol)
- Enterovirus and echovirus infection
- Fifth disease (erythema infectiosum)
- Roseola infantum (sixth disease)
- Epstein Barr virus (EBV) infection (infectious mononucleosis)
- Cytomegalovirus (CMV) infection
- Iodinated contrast media nonimmediate adverse reaction
- Toxic epidermal necrolysis/Stevens-Johnson syndrome
- Drug reaction with eosinophilia and systemic symptoms
- Erythema multiforme
- Systemic hypersensitivity syndrome
- HIV-seroconversion exanthema (also known as acute retroviral syndrome)
- Acute hepatitis B virus infection
- Acute hepatitis C virus infection
- Rubella (German measles)
- Rubeola (measles)
- Scarlet fever
- Staphylococcal scalded skin syndrome
- Toxic shock syndrome (Staphylococcus exotoxin)
- Rocky Mountain spotted fever or Mediterranean spotted fever
- Acute graft-versus-host disease
- Kawasaki disease (mucocutaneous lymph node syndrome)
- Juvenile-onset or adult-onset Still disease
- Syphilis (secondary)
- Ebola virus infection
- Zika virus infection
- Chikungunya virus infection
- Dengue fever
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