Diagnosis: Gianotti-Crosti syndrome
Gianotti-Crosti syndrome (GCS) is a pediatric disease whose incidence and prevalence are unknown. Children who have GCS may be given a diagnosis of “nonspecific viral exanthem” or “viral rash” and, as a result, the condition may be underdiagnosed.1
GCS—also known as papular acrodermatitis of childhood—affects children between the ages of 6 months and 12 years.2 The pathogenesis of GCS is unclear, but is believed to involve a cutaneous reaction pattern related to viral and bacterial infections or to vaccination.3 It is associated with the hepatitis B virus, Epstein-Barr virus, enteroviruses, parainfluenza viruses, and other viral infections. The eruption has also occurred following vaccination (hepatitis A, others).4
GCS is usually diagnosed clinically. Physical examination typically shows discrete, monomorphous, flesh-colored or erythematous flat-topped papulovesicles distributed symmetrically on the cheeks and on the extensor surfaces of the extremities and the buttocks. The trunk, palms, and soles are usually spared. This distribution pattern is responsible for the name “papular acrodermatitis of childhood.” The lesions are usually asymptomatic, but may be accompanied by a low-grade fever, diarrhea, or malaise.5
Avoid confusing GCS with these 4 conditions
The differential diagnosis for GCS includes miliaria rubra, papular urticaria, lichen nitidus, and molluscum contagiosum.
Miliaria rubra (“prickly heat”) is caused when keratinous plugs occlude the sweat glands. Retrograde pressure may cause rupture of the sweat duct and leakage of sweat into the surrounding tissue, thereby inducing inflammation. Most cases of miliaria rubra occur in hot and humid conditions. However, infants may develop such eruptions in winter if they are dressed too warmly indoors.4
Miliaria rubra manifests as superficial, erythematous, minute papulovesicles with nonfollicular distribution. The lesions, which cause a prickly sensation, are typically localized in flexural regions such as the neck, groin, and axilla, and may be confused with candidiasis or folliculitis.