Scarlet fever in Adult
A 2-5 day incubation period precedes the onset of rash. Associated prodromal symptoms include fever and malaise. Sore throat and swollen, tender anterior cervical lymph nodes are typical. Abdominal pain, nausea, and vomiting are common in younger children. Petechiae may be present on the soft palate.
The characteristic rash begins within 12-48 hours of fever onset. It initially presents on the trunk and spreads to involve the extremities, sparing the palms and soles. The rash is often accentuated in flexural creases. It manifests as confluent tiny, erythematous papules with a "sandpaper-like" appearance. Enlarged tongue papillae may give the appearance of a "strawberry tongue." The rash tends to fade in a week and is followed by desquamation.
Once a fatal disease in the pre-antibiotic era, scarlet fever's associated complications are now fortunately rare with the existence of effective antibiotic therapy. However, meningitis, otitis, sinusitis, pneumonia, arthritis, rheumatic fever, and glomerulonephritis can still rarely occur as in any streptococcal infection.
In 2022-2023, the United Kingdom reported a surge in scarlet fever that coincided with an increase in invasive S pyogenes (invasive group A strep [iGAS]) infections. In the United States and elsewhere in Europe, iGAS infections in children, including necrotizing fasciitis and streptococcal toxic shock syndrome, have increased without a concomitant increase in cases of scarlet fever.
A38.9 – Scarlet fever, uncomplicated
30242009 – Scarlet fever
Differential Diagnosis & Pitfalls
- Toxic shock syndrome originates from Staphylococcus aureus infections arising in the setting of super-absorbent tampons, nasal packing, or surgical site infections. Patients are systemically ill and eventually desquamate.
- Staphylococcal scalded skin syndrome (SSSS) usually occurs in young children following an S aureus infection. The affected skin is notably tender.
- Kawasaki disease is characterized by strawberry tongue, conjunctival injection, cervical lymphadenopathy, and rash. This is also more common in children.
- Exanthematous drug eruptions will have a history of exposure.
- Viral exanthems (such as roseola or coxsackie virus, among others).
- Sunburns occur after sun exposure and are photodistributed.
- Photosensitive and phototoxic drug eruptions are photodistributed.
- Photocontact dermatitis is photodistributed.
- Rubeola has associated cough, coryza, conjunctivitis, and Koplik spots.
- Rubella has occipital and postauricular lymphadenopathy.
- Rat-bite fever
- Infectious mononucleosis has associated lymphadenopathy.
- Primary human immunodeficiency virus (HIV) infection is characterized by lymphadenopathy and rash.
- Lupus erythematosus has associated photosensitivity.