Initial (catarrhal) period
The development of the clinical picture follows a strict cyclic pattern. The first, catarrhal period lasts from 1 to 8 days (most often 3–4 days). The disease starts acutely: body temperature rises sharply, weakness and headache increase, and abdominal pain and diarrhea may appear. Fever usually stays high and gradually decreases by the time the rash appears.
Intoxication is accompanied by prominent catarrhal inflammation. The respiratory tract responds with nasal congestion, serous rhinitis, and a harsh, dry, “barking” cough. Ocular manifestations include conjunctival hyperemia, scleral vessel injection (scleritis), lacrimation, and photophobia. The patient's face becomes puffy and the eyelids swell.
On days 1–2, enanthem appears on the soft and hard palate as small red spots that soon merge with the general hyperemia. From the second day, Koplik's spots form. This is a crucial pathognomonic marker: slightly elevated whitish areas of necrotic epithelium resembling adhered "semolina grains" with a hyperemic halo. They are usually located on the buccal mucosa opposite the lower molars and disappear by the time massive skin rashes appear.
Peak (eruption) period
This stage lasts 3–4 days. From the moment the rash appears, well-being sharply deteriorates: there is a new temperature spike (up to 39°C and above), lethargy, drowsiness, and anorexia increase. Catarrhal symptoms reach their maximum — eyelids may stick together from purulent crusts, and photophobia worsens.
Measles exanthem is characterized by a strict top-to-bottom staging:
- Day 1: lesions appear behind the ears, on the bridge of the nose, then cover the entire face, neck, and sporadically the chest.
- Day 2: the rash densely and evenly covers the trunk and arms.
- Day 3: the rash involves the legs, while the lesions on the face are already beginning to fade.
The rash is maculopapular (papules about 2 mm), the elements tend to coalesce, but are always located against the background of unaffected skin (unaffected areas are always present). At the height of intoxication, tachycardia and a drop in blood pressure are noted. Dry rales are heard in the lungs. The liver and spleen are not enlarged, but decreased diuresis is possible.
Important: persistence of high fever after the completion of the rash stage is a reliable sign of complications developing.
Convalescence (pigmentation) period
Takes 5 to 8 days in uncomplicated cases. Temperature normalizes critically or lytically, appetite returns, and respiratory symptoms gradually subside. However, asthenic syndrome may persist for a long time: rapid fatigue, irritability, and insomnia.
The evolution of skin lesions follows the same top-to-bottom rule. The exanthem fades in stages, leaving brownish-black spots (pigmentation) behind. This process is accompanied by fine branny desquamation, which is most pronounced on the face, and mild skin itching.
Laboratory diagnostics
To confirm the diagnosis, the following methods are primarily used:
- Serological assay: detection of a rise in antibody titer in paired sera (4-fold or more). In ELISA, the detection of IgM class antibodies confirms acute infection, while IgG indicates a past disease or immunization.
- Cytoscopic method: microscopy of nasal secretions to look for specific multinucleated giant cells (symplasts).
- Virological method: isolation of the pathogen in human or monkey kidney cell cultures (used mainly for research purposes due to the long observation period of up to 30 days).
Routine CBC shows non-specific changes: leukopenia, neutropenia, relative lymphocytosis; ESR remains within normal limits.
Briefly: answers to topical questions
What clinical forms of measles are considered atypical?
Atypical forms of measles include the following variants of the disease course:
- Mitigated — proceeds mildly; temperature is normal or subfebrile, Koplik's spots are absent, catarrhal symptoms are mild, the rash is sparse, and rash staging is absent. Typical for individuals who received antimesoelas immunoglobulin at the beginning of the incubation period; also described in individuals who received blood products, plasma, or immunoglobulins during the incubation period.
- Abortive — starts typically, but cuts short with normalization of temperature on days 1–2 from the appearance of sparse exanthem on the face and trunk; pigmentation is short-lived.
- Mild (attenuated) — typical clinical symptoms are absent; observed in infants in the first half of life due to residual passive maternal immunity. Mild and transient symptoms of intoxication and catarrhal phenomena are also described.
- Asymptomatic — clinical manifestations are absent, diagnosis is based solely on serological tests.
What are the indications for hospitalization of measles patients?
Indications for hospitalization of measles patients include a moderately severe and severe course of the disease, as well as social indications. In most cases, treatment is carried out on an outpatient basis.
In the absence of indications for hospitalization, bed rest, abundant fractional drinking under the control of diuresis, and thorough care of the oral cavity and eye mucous membranes are prescribed. Due to pronounced photophobia, the patient is placed in a room with dimmed lighting, without bright sunlight; bed rest is maintained until complete normalization of body temperature.
The "rain" rule for measles: the rash "falls" from top to bottom. Day 1 — head and neck get wet, Day 2 — trunk, Day 3 — legs. The rash leaves (pigments) in the exact same order.
Class and exam questions
How to distinguish measles rash from rubella rash?
In measles, the rash is large, confluent, appears in stages over 3 days and leaves brown pigmentation with desquamation. In rubella, the rash is fine-spotted, does not coalesce, covers the body in a few hours, and disappears without a trace.
Does measles occur without classic symptoms and rash?
Yes, there are mild (in infants with residual maternal antibodies) and asymptomatic forms, which are diagnosed only using serological tests (ELISA).
What complications are most characteristic of measles?
Specific complications are caused by the virus itself at the peak of the disease (measles croup, encephalitis, viral pneumonia). Non-specific ones are associated with secondary bacterial flora (purulent otitis, bacterial pneumonia, blepharitis).
What else to study on this topic
- Atypical forms: mitigated, abortive, mild
- Differential diagnosis with scarlet fever and infectious mononucleosis
- Pathogenesis of slow viral infection (SSPE)
- Criteria for assessing infection severity
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