Gianotti-Crosti syndrome (GCS) is a sudden onset of rash in children aged 15 months to 2 years that may be associated with immunization or an acute infectious disease. The most common inciting factor in GCS is infection with Epstein-Barr virus (EBV). Although GCS is usually asymptomatic, it may cause mild pruritus. The rash lasts from 2 to 4 weeks but can be present for as long as 4 months. Recurrent episodes are rare  .
In general, children affected with GCS do not appear to be ill but have multiple discrete papular and papulovesicular eruptions on the cheeks, extensor surfaces of the extremities and the buttocks. The distribution is symmetrical and acral. The individual monomorphous papules range from 1 to 5 or 10 millimeters and can have a range of color from flesh-toned to erythematous to red-brown. They have a flat top and may coalesce to form larger plaques. However, development of a petechial or purpuric appearance is uncommon. The papules may acquire a lichenoid appearance over days to weeks. It usually resolves after 10 to 60 days but new lesions may appear for 8 to 11 weeks  . One report has shown that all cases with an exclusive eruption on the face were infected with EBV .
The most important etiologic factor is an infection but immunomodulation can further accentuate the condition and this explains the association of GCS with vaccination .
Other physical findings on examination may include fever (27%), lymphadenopathy (31%), hepatosplenomegaly (4%), and oropharyngeal vesicles or ulcers, pharyngeal erythema, or tonsillar swelling. Axillary or inguinal adenopathy, hepatosplenomegaly, and an extensive involvement of the trunk are considered as inconsistent findings in GCS.
Entire Body System
- Constitutional Symptom
Prodrome might occur, suggesting upper respiratory infection, or constitutional symptoms. Diagnosis is eminently clinical, and this disease is associated with viral infections. [ncbi.nlm.nih.gov]
The condition was not associated with or preceded by fever or other constitutional symptoms. There was no family history of similar complaints. [mjmsr.net]
Constitutional symptoms are usually mild; low-grade fever and lassitude sometimes occur. Pruritus is not a prominent feature, and excoriations are never seen. Lymphadenopathy is common but does not occur in every case. [plasticsurgerykey.com]
- Pediatric Disease
Diseases Acrokeratoelastoidosis Acropustulosis of Infancy Acute Hemorrhagic Edema of Infancy Alezzandrini Syndrome Aplasia Cutis Congenita Asymmetric Periflexural Exanthem of Childhood Ataxia-Telangiectasia Atrophia Maculosa Varioliformis Cutis Bloom [dokterairlangga.com]
- Koebner Phenomenon
phenomenon in the lesions  have been reported and even prolonged course of more than 2 months and recurrences which is rare also has been seen.  Laboratory findings are not characteristic. [mjmsr.net]
Koebner's phenomenon may also be present [2-4]. Although the exact underlying pathophysiologic mechanisms remain unclear, GCS is considered a cutaneous response to various immunologic triggers, with viral infections being the key factor. [synapse.koreamed.org]
The rash of Gianotti-Crosti may display the koebnerization phenomenon. Diagnosis confirmation There is no definitive serologic testing to confirm the diagnosis. Differential diagnosis includes the conditions below. [dermatologyadvisor.com]
During the early phase of the disease, Koebner’s phenomenon may be seen. Mucosal surfaces are not affected. Systemic ﬁndings may include malaise, low-grade fever, or diarrhea. [dermapress.wordpress.com]
The appearance of lesions at sites of trauma (ie, the Koebner phenomenon) may be seen during the early phase [12,63]. Pruritus usually is of mild to moderate severity; however, the spectrum ranges from absent to severe. [fr.slideshare.net]
- Palpable Purpura
Immunoglobulin A vasculitis (formerly Henoch-Schönlein purpura) presents with palpable purpura on the legs, arms, and buttocks with associated abdominal pain and arthritis. [visualdx.com]
It is characterized by palpable purpura in patients with neither thrombocytopenia nor coagulopathy (picture 11A-B), arthritis/arthralgia, abdominal pain, and renal disease. [fr.slideshare.net]
- Facial Papule
It is important to remember that some truncal lesions do not exclude a diagnosis of GCS.15 There are also reports of GCS presenting with only facial papules,20 although such cases would not fit Chun's criteria. [healio.com]
Face, Head & Neck
The proposed diagnostic criteria for GCS is as follows  :
- Presence of monomorphous, pink to brown papules or papulovesicles with a flat top and 1 to 10 millimeters in diameter; at least three of these four sites have to be involved: cheeks, extensor surfaces of legs, extensor surfaces of the forearms, buttocks; symmetrical eruption; duration should be at least 10 days
- The absence of an extensive eruption on the trunk and scaling.
- Exclusion of other diagnoses based on their clinical features.
- If skin biopsy is done, a compatible histological finding.
Laboratory studies are generally not needed to diagnose GCS but the presence of jaundice or hepatomegaly should raise suspicion of hepatitis B virus infection and tests may reveal elevated liver enzymes, although elevated liver enzymes are mostly related to EBV infection.
Findings on skin biopsy can help rule out other conditions since they are not specific for GCS. Focal spongiosis, mild acanthosis, parakeratosis, and psoriasiform hyperplasia can be observed in the epidermis . The dermis shows moderate perivascular infiltrate of lymphocytes and histiocytes, while eosinophils are scattered occasionally . The papillary dermis reveals extravasated erythrocytes .
LABORATORY The peripheral blood may show modest lymphocytosis or lymphopenia. Occasionally the number of monocytes is increased, probably in patients with EBV. If the liver enzymes are elevated, the usual cause is EBV or CMV. [dermapress.wordpress.com]
Patients with GCS may have modest lymphocytosis or lymphopenia . Liver enzymes may be elevated in patients with EBV, CMV, or hepatitis- 3. associated disease. Skin biopsy may be useful in cases that are clinically confusing. [fr.slideshare.net]
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- Yoshida M, Tsuda N, Morihata T, et al. Five patients with localized facial eruptions associated with Gianotti-Crosti syndrome caused by primary Epstein-Barr virus infection. J Pediatr. 2004;145(6):843-4.
- Baldari U, Monti A, Righini M. An epidemic of infantile papular acrodermatitis (Gianotti-Crosti syndrome) due to Epstein-Barr virus. Dermatology. 1994;188:203–204.
- Chuh A, Zawar V, Sciallis GF, Lee A. The diagnostic criteria of pityriasis rosea and Gianotti-Crosti syndrome - a protocol to establish diagnostic criteria of skin diseases. J R Coll Physicians Edinb. 2015;45(3):218-25.
- Chuh AA. Diagnostic criteria for Gianotti-Crosti syndrome: a prospective case-control study for validity assessment. Cutis. 2001;68(3):207-13.
- Retrouvey M, Koch LH, Williams JV. Gianotti-Crosti syndrome following childhood vaccinations. Pediatr Dermatol. 2013;30(1):137-8.