Non-Specific Viral Exanthems

Case
A 10 month old boy is brought to your office because of an extensive rash. The child was seen 2 days ago in the ER because of a febrile illness and diagnosed with a right otitis media. He was started on Amoxicillin. The rash began last night on the face and is now all over. There a temperature of 37.9 and some irritability. There is a maculopapular rash all over and the ears are normal. What would you do?

An exanthem is a generalized cutaneous eruption associated with a systemic illness, most often of infectious origin. It represents either a reaction to a toxin produced by the organism, damage to the skin by the organisms, or an immune response. 

Exanthems secondary to viral infections are very common during childhood. When there are no characteristic lesions, distinctive prodrome, oral manifestations, nor symptom complexes, diagnosis of a specific etiology may be very difficult. Because the children are often not toxic and the illnesses last only a short time, a specific diagnosis may not be possible. Only if there has been exposure to a pregnant woman or an immunoincompetent host, will identification be important. Pertinent history and physical exam:

  1. distribution and evolution
  2. infectious exposure
  3. general symptoms
  4. drug exposure
  5. time of year
  6. complete physical examination

These rashes must be distinguished from those associated with Kawasaki's Disease, Rickettsial diseases, bacterial processes like scarlet fever and toxic shock, Staphylococcal Scalded Skin Syndrome, and meningococcemia. If initial evaluation does not produce a diagnosis, careful follow-up is important. 

In many instances, the picture is confused by the fact that the child is taking some antibiotic and it may be difficult to distinguish a drug rash or allergic drug reaction from a non-specific viral exanthem. Should the child be kept off that particular medicine in the future? In most instances this needs to be discussed with the parents. If the child needs to take that medicine again, they should get the first dose in the presence of the doctor and wait 30 minutes before leaving their office. 

The majority of non-specific rashes are maculopapular, blanching, more extensive on the trunk and extremities, and usually not pruritic. During the respiratory viral season, common etiologies include adenoviruses, parainfluenza viruses, RSV, and influenza. During the warm weather months, most are due to enteroviruses. 

Treatment entails treating symptoms and reassurance.

References

  1. Mancini AJ. Exanthems in Childhood: An Update. Pediatric Annals. 1998; 27(3):163-170.
  2. Resnick SD. New Aspects of Exanthematous Diseases of Childhood. Dermatologic Clinics. 1997; 15(2):257-266.\

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