Exanthems in children are often benign and self-limited, but not always.
In some cases – particularly those involving purpura, blisters, mucosal involvement, a high fever, or extracutaneous organ involvement – it is important to thoroughly evaluate the child for more serious disease, Dr. Anthony J. Mancini said at the seminar, sponsored by the Skin Disease Education Foundation (SDEF).
Dr. Anthony J. Mancini
Dr. Mancini, head of the division of dermatology at the Ann and Robert H. Lurie Children’s Hospital of Chicago and professor of pediatrics and dermatology at Northwestern University, Chicago, provided tips for assessing the child presenting with an exanthem:
• If purpura is present, consider parvovirus, enterovirus, rickettsia, Neisseria meningitidis, Henoch-Schönlein purpura, and even group A strep.
• If edema is present, consider Kawasaki disease, serum sickness-like reactions (most often distal edema), or drug hypersensitivity syndrome (notable for facial edema, especially periorbitally).
• If an associated enanthem is present, consider Kawasaki disease, drug hypersensitivity, measles, rubella, enterovirus, parvovirus, adenovirus, group A strep, and Epstein-Barr virus (EBV).
• If conjunctivitis is present, consider Kawasaki disease, drug hypersensitivity, measles, and adenovirus (the most common mimicker of Kawasaki disease in children).
Parvovirus B19 Infection
Among the exanthems that Dr. Mancini discussed were those related to parvovirus B19 infection, including erythema infectiosum (fifth disease) and papular-purpuric gloves and socks syndrome. The latter entity is notable for symmetric swelling of the hands and feet, with palmoplantar purpuric erythema and a sharp demarcation at the wrists and ankles.
Children with gloves and socks syndrome may also present with enanthem of the soft and hard palate, and importantly, children with this exanthem may still be viremic (and hence contagious), compared with those who have classic fifth disease, he said.
Parvovirus B19 can also be associated with a bathing trunk eruption with petechiae, notable for accentuation in the flexures and a prominent petechial component. The infection was found to be the culprit in 13 of 17 children who presented with generalized petechial exanthems in a study based in Wisconsin, Dr. Mancini said. These exanthems also revealed accentuation in the fold areas, as well as the acral extremities. Fever was present in 85% of patients, and many had a history of mild upper respiratory symptoms. Additionally, most of the children (83%) had leukopenia (Pediatrics 2010;125:e787).
Breakthrough Varicella
Breakthrough varicella still occurs in a significant proportion of varicella vaccinees, especially in children from countries with a one-dose vaccination schedule, such as Taiwan.
This association is important to recognize, given that many practicing clinicians may have never seen acute varicella. The "dewdrop on a rose petal" presentation is characteristic, but lesions may also develop severe crusting or ulceration when secondary bacterial infection is present. Acute varicella may also accentuate in sites of trauma or sunburn, and has been termed "occult varicella," he noted.
Herpes zoster, caused by reactivation of latent varicella zoster virus (VZV) in the dorsal sensory or cranial nerve ganglia, is not unusual in healthy children and may be caused by either the wild type or vaccine strain of VZV, he said.