Stage 1: Anamnesis and clinical assessment
Primary diagnosis is based on identifying diagnostically significant information from complaints and physical examination. The onset of the disease is always acute, accompanied by pronounced intoxication syndrome: fever, headache, weakness, and in children, frequently vomiting.
Key markers on physical examination:
- Oropharyngeal involvement: acute catarrhal or catarrhal-purulent tonsillitis develops. A pathognomonic sign is the «flaming fauces» (bright, diffuse hyperemia), with a strict absence of hyperemia on the mucous membrane of the hard palate.
- Dynamics of tongue changes: at the onset of the disease, the tongue is heavily coated with greyish-yellow plaque. From the 2nd–3rd day, it begins to clear from the tip and edges, acquiring a bright red color with prominent hypertrophied papillae («raspberry tongue»).
- Skin syndrome: within the first hours, an abundant punctate rash appears on a generalized hyperemic background of the skin. The elements characteristically cluster in natural skin creases. Pronounced white dermographism is noted.
- Specific symptoms: a pale nasolabial triangle (Filatov's sign) and dark red lines in skin folds (Pastia's sign) are revealed. In later stages, skin desquamation is characteristic.
- Lymphatic system: enlarged regional (predominantly anterior cervical) lymph nodes are palpable.
Stage 2: Laboratory confirmation and differential diagnosis
The second stage aims at precise confirmation of scarlet fever and assessment of the body's condition.
- Laboratory tests:
- Complete blood count (CBC): reflects the bacterial nature of inflammation — neutrophilic leukocytosis with a band shift and elevated ESR are detected.
- Urinalysis: febrile albuminuria is possible against the background of high fever.
- Specific diagnostics: bacteriological and serological studies to verify group A streptococcus.
- Search for complications: if necessary, the algorithm is expanded with imaging and ultrasound diagnostics, ECG recording, additional bacterial cultures, and consultations with subspecialists (otorhinolaryngologist, cardiologist, nephrologist).
- Differential diagnosis: performed with other infectious diseases having a similar exanthem and tonsillitis syndrome. The final conclusion is formulated at the intersection of clinical, laboratory, and anamnestic data.
Epidemiology and hospitalization
Epidemiological history is not always obvious, as the source of infection includes not only patients with streptococcal infections, but also healthy GAS carriers. Incidence peaks usually correlate with the change in the leading serotype of the pathogen (determined by the M-protein structure).
Indications for mandatory hospitalization:
- Moderate and severe forms of scarlet fever.
- Patients from closed children's institutions (orphanages, sanatoriums, boarding schools).
- Living in the same household with children under 10 years of age who have not previously had scarlet fever.
- Inability to provide adequate home care.
- Inability to isolate the patient from family members working in vetted professions (preschool childcare facilities, maternity wards, dairy kitchens, surgery).
Focus measures and quarantine
Proper routing of convalescents and contacts is the basis of anti-epidemic work.
Admission of convalescents:
- Children attending preschools and the first two grades are admitted to the group only 12 days after clinical recovery.
- Adults from vetted groups are transferred to epidemiologically safe work for the same 12 days.
- If a case of tonsillitis is detected in a scarlet fever focus within 7 days, such a patient is equated to a scarlet fever patient (suspension for 22 days from the onset of the disease).
Quarantine in children's institutions: Imposed on the group for 7 days from the moment of isolation of the last patient. Daily thermometry, skin and throat examination are required. Any contacts with acute respiratory infections or tonsillitis are immediately suspended, examined for a rash, and their return is permitted only after full recovery and submission of a certificate of antibiotic therapy.
Dispensary observation: Convalescents are observed for 1 month. 7–10 days after discharge, clinical and laboratory monitoring is scheduled (blood and urine tests, ECG as indicated). In the absence of pathology after 3 weeks, the patient is removed from registration; if abnormalities are detected, they are referred to a subspecialist.
Briefly: answers to topical questions
What infectious diseases are included in the differential diagnosis of scarlet fever?
Differential diagnosis of scarlet fever must be performed with diseases having a similar clinical course. First of all, differential diagnosis is carried out with the following diseases:
- Measles
- Rubella
- Yersiniosis (pseudotuberculosis)
- Infectious mononucleosis
- Diphtheria (in rare cases with the development of fibrinous plaques extending beyond the tonsils)
- Allergic dermatitis (drug dermatitis, toxicoderma).
What early and late complications can develop after suffering from scarlet fever?
Bacterial and immunopathological complications may develop after suffering from scarlet fever.
- Bacterial complications (early and late) — purulent lymphadenitis, periadenitis, adenophlegmon, otitis media, sinusitis, mastoiditis. In infants under one year of age, purulent complications often develop even with mild and mild/abortive forms of the disease.
- Immunopathological complications — develop in the 2nd–4th week from the onset of the disease. These include myocarditis, nephritis, glomerulonephritis, synovitis, arteritis.
What antibacterial drugs are used for etiotropic therapy of scarlet fever?
A 10-day course of antibacterial therapy is used for the etiotropic therapy of scarlet fever.
- Penicillin is the drug of choice.
- Macrolides: erythromycin, azithromycin are alternative drugs.
- First-generation cephalosporins: cefazolin are alternative drugs.
- Semisynthetic penicillins and lincosamides are used in case of contraindications to the above drugs.
For quick memorization of the classic facial appearance in scarlet fever, use the rule «F-P-R»: Flaming fauces — Pale nasolabial triangle (Filatov's) — Raspberry tongue.
Class and exam questions
What is the specific feature of oropharyngeal hyperemia in scarlet fever?
Hyperemia is bright and diffuse («flaming fauces»), yet it is clearly demarcated — the mucous membrane of the hard palate remains normal (not hyperemic).
How does the patient's tongue change over time?
At the beginning of the disease, it is covered with a thick greyish-yellow plaque. From the 2nd–3rd day, the tongue begins to clear from the edges and tip, acquiring an intense red color with prominent hypertrophied papillae («raspberry tongue»).
Who must be mandatorily hospitalized for scarlet fever?
Mandatory hospitalization is subject for patients with severe forms, pupils of closed children's institutions, as well as patients who cannot be isolated from children under 10 years old (who have not previously had the disease) or from relatives of vetted professions.
What is the management strategy when tonsillitis is detected in a scarlet fever focus?
Any patient with tonsillitis detected in the focus within 7 days after the last case is epidemiologically equated to a scarlet fever patient. Admission to children's institutions or vetted work is allowed only 22 days after the onset of the disease.
What else to study on this topic
- Structure of M protein and mechanisms of dominant GAS serotype shifting
- Specific skin signs: Pastia's lines and Filatov's sign
- Management tactics for ARVI cases in closed epidemic foci
- Admission rules for adults in high-risk (decreed) professions after contact
- Follow-up (dispensary monitoring) algorithm and de-registration criteria
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