Briefs: Seeing red

A mom brings her six year old son into the ED with concerns of fever and rash. She is concerned that he caught his sister’s pneumonia – and that he is super uncomfortable because of his sunburn. On exam he looks OK, and has a fever of 38.7 C. His vitals, aside from a HR of 110 BPM are not alarming. Here are some of his exam findings:

A really red tongue

Not sunburn…

His rapid strep test is positive. What is the diagnosis?

Click the toggle box below for the answer.

[toggle_box] [toggle_item title=”Diagnosis” active=”false”]Scarlet Fever[/toggle_item] [/toggle_box]

What is it?

A systemic infection caused by exotoxin producing strains of Streptococcus pyogenes (Group A Strep). Not all strains of GAS produce the toxin, only the obstreperous ones “lucky” enough to be infected with a toxin granting bacteriophage. It generally manifests in fever, sore throat and rash and is most common in children aged 4-8 years with a slight male predominance. It is rare after 10, since most patients have acquired an antibody to the exotoxin. The diagnosis is clinical but can be supported by rapid strep test and throat culture/confirmatory DNA assay.

What are the classic findings?

Oral

Strawberry tongue, as seen above
Palatal petechiae, erythema and exudate – the first two are pictured below

Palatal petechiae and erythema

Cutaneous

Erythematous, blanching, fine and rough – sandpapery some might say!
Appears within 3 days of onset of fever
Starts centrally – especially the chest, armpits and behind the ears
Circumoral pallor is common

Facial erythema with circumoral pallor

Prominent Pastia Lines in the intertriginous areas which can persist even after the main rash is gone

Pastia’s Lines in the antecubital fossa

Fades 3-4 days after starting, followed by peeling

Peeling soles

Peeling skin

How do you treat it?

With antibiotics… OK, more specifically pencillins (I’d advocate for amoxicillin in kids since it tastes better and is still dirt cheap). You can use clindamycin or erythromycin in penicillin allergic patients, though erythromycin resistant strains have been found in Hong Kong recently.