Gianotti-Crosti Syndrome (aka Papular Acrodermatitis of Childhood)

Gianotti-Crosti syndrome (GCS) is a clinically distinct viral exanthem, originally thought to occur secondary to hepatitis B, but now known to occur following infection with several viral triggers or after vaccinations.
The eruption most often occurs in young children in the spring and early summer.

GCS is a cutaneous response to various infections and has been linked to numerous viral agents including Epstein-Barr virus (EBV), cytomegalovirus, parvovirus, coxsackie virus, respiratory syncytial virus, rotavirus, and influenza A, among others.

GCS is often preceded by a mild prodrome that can include constitutional symptoms, lymphadenopathy, and/or upper respiratory symptoms.
The eruption of GCS is characterized by monomorphic skin-colored to pink edematous papules and papulovesicles distributed symmetrically on the extensor surfaces of the upper and lower extremities, buttocks, and face (Figs. 7.10 and 7.11).
Papules may coalesce to pink edematous plaques.
The trunk is notably spared.
It is usually asymptomatic although pruritus may be present.

Diagnosis is based on clinical recognition.
After a thorough history and physical examination, laboratory tests to detect a specific viral etiology should be performed if clinically indicated.

Differential Diagnosis

Id Reaction (see Chapter 13: Eczema and Related Disorders)

An itchy, eczematous eruption that can present as monomorphic erythematous or skin-colored papules localized to the extensor elbows and knees resembling GCS.
Also called autoeczematization, an Id reaction is usually triggered by a severe inflammatory dermatosis such as allergic contact dermatitis, molluscum contagiosum, or fungal infections.

Drug Eruption (see Chapter 26: Adverse Cutaneous Drug Eruptions)

Pink-red blanching macules and papules that begin on the face and neck and spread caudally.
Pruritus is common.
History of inciting drug ingestion in the preceding 7 to 14 days.

Molluscum Contagiosum (see Chapter 6: Superficial Viral Infections)

Molluscum, particularly when inflamed and located on the extensor knees and elbows, can mimic GCS.

Management

Gianotti-Crosti syndrome is self-limited; spontaneous resolution usually occurs within 3 to 4 weeks but may take 8 to 12 weeks.
Lymphadenopathy may persist for 2 to 3 months.
Lesions may resolve with postinflammatory hyperpigmentation.
Treatment is supportive.
If pruritic, topical corticosteroids and antipruritic creams may provide some benefit.

Helpful Hint

A Gianotti-Crosti syndrome-like eruption can also occur as a response to molluscum contagiosum and often heralds resolution of molluscum. This eruption is often pruritic.

Point to Remember

The extent and intensity of the eruption can be impressive and recognition of the characteristic distribution and morphology of GCS can help to quickly reassure parents.