| • | pathogen = group A beta-hemolytic streptococci (Streptococcus pyogenes) |
| • | toxin = streptococcal pyogenic exotoxin A (AKA Scarlet fever toxin) |
| • | the toxin is responsible for the rash and the systemic symptoms |
clincal:
| • | sudden onset fever and pharyngitis |
| • | begins on neck and face and spreads diffusely |
| • | vivid scarlet hue with innumerable pinpoint papules that give a sandpaper quality to the skin |
| • | enanthem: strawberry tongue; entire oral cavity may be red |
| • | Pastia’s sign: linear petechiae characteristically found in the skin folds (especially antecubital fossae and inguinal area) |
| • | more pronounced post-exanthem desquamation than other exanthems (may last up to 8 weeks) |
| • | the pattern of desquamation of the palms and soles and grooving of the nails (Beau’s lines) is such a distinct characteristic of scarlet fever that in can make a retrospective diagnosis |
summary:
| • | “sandpaper” rash, circumoral pallor, Pastia’s lines, strawberry tongue |
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