• It occurs with group A beta hemolytic strep infection.
• It develops with erythrogenic toxin released from streptococci during acute tonsillitis.
• Incubation period is 1-7 days.
• A maculopapular rash occurs on the skin and is sterile because it is only due to the toxin.
Clinic
• It starts like acute tonsillitis. A maculopapular rash begins 24-48 hours after these symptoms.
• 1-2. day white strawberry tongue
• 4-5. day red strawberry tongue
• There may be many petechiae on the palate. The uvula and soft palate are erythematous and edematous.
• The rash appears 24-48 hours after the first symptoms. The rash begins on the face and eventually spreads to the trunk and extremities.
• The skin is rough like a plucked chicken.
• Pale around the mouth (peroral pallor)
• There are petechial lines parallel to the skin folds within the hyperemic areas in the folds of the skin such as the axilla, inguinal and antecubital region. These are called "Pastia lines".
• If the skin is scratched with a hard object in the first 5 days, a white line lasting 2 minutes will occur. This is called "dermographism". "Miliary Sudamina" are small vesicular lesions that develop on the abdomen, hands, and feet in severe scarlet fever.
• The scarlet rash eventually heals with desquamation. This peeling is in the form of flaking and starts on the forehead. Hands and feet are the last parts to desquam.
• Desquamation starting from the free ends of the nails is characteristic.
laboratory findings
• Throat culture positivity
• ASO (>200 Todd units)
• Anti DNAase antibody (best laboratory finding for streptococcal pyoderma)
• Antihyaluronidase antibody (although not as valuable as ASO, it is helpful in diagnosis)
• Shultz-Charlton phenomenon: The rash fades when an anti-erythrogenic toxin antibody is applied to the skin lesion.
Treatment
• Penicillin is used during acute infection.
• Erythromycin, chloromphenicol, lincomycin or clindamycin can be tried as a last option for those who are allergic to penicillin.
• Prophylaxis against streptococci is performed only in acute joint rheumatism (ARA).
• Sulfonamides are contraindicated, they increase the risk of ARA as they provide delayed recovery.