The cutaneous eruption of scarlet fever accompanies a streptococcal infection at another anatomic site, usually the tonsillopharynx. The illness generally has a 1- to 4-day incubation period. Its emergence tends to be abrupt, usually heralded by sudden onset of fever associated with sore throat,  headache, chills, nausea, myalgias, and malaise. Young children may also present with vomiting, abdominal pain, and seizure. The characteristic rash appears 12-48 hours after the onset of fever, first on the neck and then extending to the trunk and extremities.
In the untreated patient, fever peaks by the second day (temperature as high as 103-104°F) and gradually returns to normal in 5-7 days. Fever abates within 12-24 hours after initiation of antibiotic therapy.
A recent history of exposure to another individual with a “strep” infection may aid in the diagnosis.
The patient usually appears moderately ill. Fever may be present. The patient may have tachycardia. Tender anterior cervical lymphadenopathy may be present.
The mucous membranes usually are bright red, and scattered petechiae and small red papular lesions on the soft palate are often present.
On day 1 or 2, the tongue is heavily coated with a white membrane through which edematous red papillae protrude (classic appearance of white strawberry tongue). By day 4 or 5, the white membrane sloughs off, revealing a shiny red tongue with prominent papillae (red strawberry tongue). Red, edematous, exudative tonsils (see the image below) are typically observed if the infection originates in this area.
Generally, the exanthem develops 12-48 hours after the onset of fever, first appearing as erythematous patches below the ears and on the neck, chest, and axilla. The characteristic exanthem consists of a fine erythematous punctate eruption that appears within 1-4 days after the onset of the illness. The eruption imparts a dry, rough texture to the skin that is reported to resemble the feel of coarse sandpaper. The erythema blanches with pressure. The skin can be pruritic but usually is not painful. Dissemination to the trunk and extremities occurs over 24 hours. It is usually more prominent in flexural areas (eg, axillae, popliteal fossae, and inguinal folds). It may also appear more intense at dependent sites and sites of pressure, such as the buttocks., Eventually scarlet macules are seen overlying the generalized erythema (“boiled-lobster” appearance).
Capillary fragility is increased, and rupture may occur. Often, transverse areas of hyperpigmentation with linear arrays of petechiae in the axillary, antecubital, and inguinal areas (Pastia lines, or the Pastia sign) can be observed. These arrays may persist for 1-2 days after resolution of the generalized rash.
Another distinctive facial finding is a flushed face with circumoral pallor. In severe disease, small vesicular lesions termed miliary sudamina may appear on the abdomen, hands, and feet.
The cutaneous rash, shown below, lasts for 4-5 days, followed by fine desquamation, one of the most distinctive features of scarlet fever. The desquamation phase begins 7-10 days after resolution of the rash, with flakes peeling from the face. Peeling from the palms and around the fingers occurs about a week later and can last up to a month or longer. The extent and duration of this phase are directly related to the severity of the eruption.
Complications of scarlet fever may include the following:
Otitis media and/or mastoiditis
Intracranial venous sinus thrombosis
Septicemia, meningitis, osteomyelitis, and septic arthritis
Acute renal failure from poststreptococcal glomerulonephritis
Sepsis with abdominal wall abscess (rarely) 
Of these, otitis media, pneumonia, septicemia, osteomyelitis, rheumatic fever, and acute glomerulonephritis are the most common. Appropriate evaluation and early intervention with antibiotics are essential to prevent these disorders.
Rare but lethal early toxin-mediated sequelae include myocarditis and toxic shocklike syndrome. A lethal form of streptococcal infection is capable of producing the toxic streptococcal syndrome.
Late complications of group A streptococcal infection include rheumatic fever and poststreptococcal glomerulonephritis. Risk of acute rheumatic fever following an untreated streptococcal infection has been estimated at 3% in epidemic situations and approximately 0.3% in endemic scenarios. If a nephritogenic strain of group A beta-hemolytic streptococci causes infection, the individual has a 10-15% chance of developing glomerulonephritis.
Weeks to months after the illness, transverse grooves (ie, Beau lines) may appear on the nail plates and hair loss (telogen effluvium) may occur.
What would you like to print?