Bacterial (purulent) complications
These conditions can occur at both early and late stages of the infectious process. Their development is directly linked to the pathogenic effect of the causative agent — group A beta-hemolytic Streptococcus (GAS). Notably, suppuration can be triggered either by the initial bacterial serotype that caused the disease or by completely different streptococcal serotypes.
This group of pathologies includes lesions of various anatomical structures:
- ENT organs: purulent otitis media, sinusitis, and mastoiditis.
- Lymphatic system: purulent lymphadenitis, periadenitis, and the formation of adenophlegmon.
Physicians should exercise special vigilance when managing infants in their first year of life. In this vulnerable age group, purulent complications often manifest even if the primary scarlet fever presented in a mild or subclinical atypical form.
Immunopathological complications
This group of complications has an infectious-allergic genesis. They are caused not by the direct impact of bacteria in the focus, but by the macroorganism's autoimmune reaction to specific streptococcal antigens.
Due to the peculiarities of pathogenesis, they have a clear temporal pattern and develop during the convalescence period, usually in the second to fourth week from the disease onset. The main forms of lesions are:
- Nephritis — damage to the renal tissue.
- Myocarditis — inflammation of the heart muscle.
- Synovitis — joint involvement.
The development of such conditions dictates the need for careful patient monitoring (including ECG and ultrasound) even after the acute manifestations of the infection have completely resolved.
Complications of the severe toxic-septic form
In severe scarlet fever with hyperpyretic fever (39.6–41.0°C) and pronounced necrotic tonsillitis (when dirty-gray necroses spread beyond the tonsils to the uvula, faucial pillars, and nasopharyngeal mucosa), the risk of life-threatening conditions increases sharply.
In such cases, against the background of deep intoxication lasting more than 7–9 days, septic complications may develop: severe necrotic angina and massive lymphadenitis. However, the most formidable condition is infectious-toxic shock (ITS). In the fulminant hypertoxic form, the buildup of intoxication occurs so catastrophically fast that decompensated ITS can lead to death in the very first days, even before the full development of typical symptoms (e.g., before the appearance of a rash).
Systemic changes in internal organs
Even with a smooth course, scarlet fever exerts a noticeable systemic effect on the patient's internal organs.
- Cardiovascular system: slight expansion of the boundaries of relative cardiac dullness to the left is possible. These cardiovascular disorders are characterized by pronounced lability, yet the patient's general condition does not noticeably worsen. The duration of such changes usually does not exceed 2–4 weeks.
- Oral cavity and gastrointestinal tract: the pathognomonic symptom of the "strawberry tongue" develops. In the first days of the disease, the tongue is thickly coated with a grayish deposit, but by the second or third day, it begins to clear from the edges and tip. As a result, it becomes completely clean, acquiring a bright red color with hypertrophied protruding papillae. This symptom persists for 1–2 weeks. Meanwhile, the mucous membranes of the oral cavity remain dry, whereas dyspepsia and hepatosplenomegaly are rare, occurring predominantly in children.
Briefly: answers to topical questions
Which antibodies to streptococcal antigens are determined in the blood for retrospective diagnosis of a past infection?
For retrospective diagnosis of a past streptococcal infection, high or rising titers of antistreptococcal antibodies are assessed in the blood:
- antistreptolysin-O (ASLO);
- anti-DNase B;
- antibodies to M-protein;
- antibodies to A-polysaccharide;
- antihyaluronidase.
Which antibiotics are the drugs of choice for treating scarlet fever and preventing complications?
For etiotropic treatment of scarlet fever, the drug of choice is penicillin. The course of antibiotic therapy is 10 days; the daily dose for adults is 6 million IU (1 million IU 6 times a day).
Natural penicillins are used for scarlet fever; penicillin-class antibiotics are also indicated as drugs of choice for the prevention of rheumatic fever relapses / rheumatic diseases.
Alternative drugs in the treatment of scarlet fever:
- macrolides: erythromycin, azithromycin;
- first-generation cephalosporins: cefazolin.
If there are contraindications to the specified drugs, semi-synthetic penicillins or lincosamides are used.
By what criteria is acute rheumatic fever diagnosed as a late complication of scarlet fever?
To diagnose acute rheumatic fever, the international Jones diagnostic criteria are used, which are divided into major and minor.
- Major criteria — carditis, polyarthritis, chorea, erythema annulare (erythema annulare/marginatum), subcutaneous rheumatic nodules.
- Minor clinical criteria — arthralgia, fever.
- Minor laboratory criteria — elevated acute-phase reactants (ESR and C-reactive protein).
- Minor instrumental criteria — prolongation of the P-R interval on the ECG.
To remember the target organs in late immunopathological complications, use the rule of the "Three H's" (Heart/myocarditis, Hoints/synovitis — joints, kidneys/nephritis).
Class and exam questions
At what week should autoimmune complications of scarlet fever be expected?
Immunopathological complications such as nephritis, myocarditis, or synovitis usually manifest in the 2nd to 4th week from the disease onset.
Do purulent complications in infants in the first year of life depend on the severity of the disease?
No, in infants, purulent processes (especially otitis media and lymphadenitis) can develop even with subclinical and mild forms of the infection.
What is the main cause of death in severe disease?
In severe toxic-septic or hypertoxic courses, the development of decompensated infectious-toxic shock (ITS) becomes the main threat to life.
Which pathogen causes bacterial complications?
They are caused by group A beta-hemolytic Streptococcus (GAS). This can be the same serotype that caused the scarlet fever itself, or other serotypes acquired later.
What else to study on this topic
- Severity criteria and clinical forms of scarlet fever
- Differential diagnosis with measles, rubella, and yersiniosis
- Key diagnostic symptoms (pastia's sign, Filatov's sign, flushed throat)
- Hemogram changes in streptococcal infection
- Regimens of antibiotic therapy with penicillins and macrolides
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