You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

Dermatologists reported an outbreak of pernio (red to purple swollen painful toes) during the COVID-19 pandemic. Most subjects lacked positive CoV-19 polymerase chain reaction (PCR) or antibodies or a preceding illness. The dermatologists termed the illness "COVID toes." Pernio usually affects adults versus "COVID toes" usually children. Pernio is preceded by a clear history of exposure to wet and cold. Patients with "COVID toes" lack this history. Also, it is not unusual for multiple family members to have "COVID toes." Our case report describes "COVID toes" in an 18-year-old with no preceding illness, a negative SARS-CoV-19 PCR, and an initially negative SARS-CoV-19 antibody, and also his 2 siblings also developed "COVID toes." In our index case, repeat SARS-CoV-19 antibodies were positive. Seroconversion has rarely been reported in patients with "COVID toes." Why most "COVID toes" patients lack a clinical history of COVID-19 and are SARS-CoV-19 PCR and antibody negative is a mystery.
["Case Report"]