Which symptom is characteristic of scarlet fever?

Punctate lesions resembling sandpaper are a hallmark of scarlet fever, which is caused by group A Streptococcus bacteria. The rash typically begins as a fine, red rash that feels like sandpaper to the touch and can cover most of the body. This distinctive rash is a key identifying feature of the condition, helping to differentiate it from other illnesses that may present with fever and rash.

In cases of scarlet fever, the rash usually develops after the onset of fever and sore throat, often accompanying other symptoms such as a "strawberry tongue" and pharyngitis. Punctate lesions can appear on the trunk and extremities, and they may be more pronounced in skin folds, reflecting the irritation caused by the toxins released by the bacteria.

Other options present symptoms that are not characteristic of scarlet fever. For instance, peering of nails is not associated with this condition, nor are erythematous macular lesions a defining symptom. The duration of fever is also inconsistent, as in scarlet fever, fever can last longer than 5 days, particularly if the infection is not properly treated. Thus, the identification of the sandpaper-like rash serves as a useful clinical clue for clinicians diagnosing scarlet fever.