Morbilliform Rashes

The term morbilliform means “measles-like.” Approximately 80% of all cutaneous drug reactions are morbilliform in nature, and many nonspecific viruses cause a morbilliform rash. True measles is rare in the developed nations because the measles vaccine is very effective.

Differential Diagnosis

• Measles
  –Also called rubeola, a highly contagious (>90% exposed patients acquire the disease), moderately severe viral illness
  –Characterized by fever and malaise in prodrome, cough, conjunctivitis, Koplick spots on buccal mucosa, and an exanthem on day 3–4
  –The exanthem of measles is blotchy, blanching, erythematous maculopapules beginning at the head and spreading distally
  –Severe complications, such as pneumonia, DIC, encephalitis, can occur

• Viral exanthems
  –Adenovirus: Many types can cause a morbilliform rash that is usually generalized when first identified, often accompanied by upper respiratory symptoms
  –Rubella (German measles): Without a prodrome in young children, the exanthem is pinkish, fine maculopapules with a distribution similar to that of measles
  –Other viruses may also cause this rash

• Drug eruptions
  –Erythematous, maculopapular rash that may be blanching or fine in nature
  –May be generalized, or begin on the trunk or face then spread to the extremities
  –Rash usually begins 1–2 weeks into therapy
  –May be pruritic
  –Drugs commonly resulting in morbilliform reactions are anticonvulsants, cephalosporins, pencillins, and sulfonamides

Workup and Diagnosis

• History
  –Presence of prodrome such as fever, upper respiratory symptoms
  –Onset and duration of rash, distribution and spread of the rash over time
  –Sick contacts, especially daycare or school
  –Immunization history, past medical history, medications

• Physical exam
  –Vital signs
  –General exam of systems with special attention to mucous membranes and HEENT exam
  –Evaluation of the characteristics of the rash such as distribution, type, confluence, blanching, and other skin findings

• Diagnostic testing is not usually needed; however, viral cultures or titers for measles can be sent if necessary to confirm diagnosis

Treatment

• Viral exanthems will resolve spontaneously in most cases
• Morbilliform drug reactions are common and resolve within a week of stopping the offending medication
• Measles
  –Isolation precautions
  –Notification of health department and infectious disease authorities
  –Supportive care including ICU when necessary; there is no specific antiviral therapy

Book Source Details

• Book Title: In A Page: Pediatric Signs and Symptoms
• Author(s): Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
• Year of Publication: 2007
• Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.

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Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: In A Page: Pediatric Signs and Symptoms Authors: Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-4051-0427-9