A 12-year-old female patient was observed in the Emergency Department due to red-violet lesions on the toes, without edema, as depicted in the images below. She reported minor trauma to the third toe of the right foot one month earlier. The girl denied pain, discomfort, pruritus, or similar previous episodes. She had the diagnosis of COVID-19 17 days earlier but was always asymptomatic. Blood tests, including coagulation studies, were performed, disclosing no significant alterations.
Discussion
Coronavirus infectious disease 2019 (COVID-19) usually has a benign course in the pediatric population, with most children being asymptomatic or presenting mild symptoms. Cutaneous manifestations related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were initially reported by Italian dermatologists, and an increasing number of cases has been identified since. They comprise maculopapular rash, urticarial lesions, chilblain-like lesions, vesicular eruptions, or thrombotic ischemic lesions.1,2
Classic chilblains, also called pernio, are characterized by the development of erythrocyanotic skin lesions in the acral region and usually represent an exacerbated skin response to nonfreezing cold exposure in susceptible individuals. They are most common in women and middle-aged adults, being relatively uncommon in children.3 Chilblains may be primary (idiopathic) or secondary to a systemic disorder.1,4 Clinically, they are characterized by single or multiple pink to violaceous macules or papules on acral surfaces, most commonly on the hands and feet. The dorsal toes or fingers are classic sites of involvement, with the heels, nose, and ears less frequently affected. Symptoms include pruritus, pain, tenderness, or burning sensation.1
Since March 2020, an increasing number of cases of chilblain-like lesions associated with COVID-19 (“COVID toes”) have been reported, with current estimates suggesting that they represent up to 19% of cutaneous manifestations of the infection.4 These cases differ from classic pernio for their predilection for younger patients (average age 12−14 years), absence of triggering factors (such as cold exposure), and balanced sex distribution. Lesions present on the feet in 74−100% of cases but can also occur on the hands and fingers.4,5 Most patients are asymptomatic or mildly symptomatic and may present with local pain or itching. Figure 1 and 2.
Little is known about the pathogenesis of these lesions. Some theories postulate that COVID-19 may be responsible for coagulation disorders and an increased risk of thromboembolism leading to acral ischemia.2,3
Polymerase chain reaction (PCR) of nasopharyngeal SARS-CoV-2 samples is negative in most children with pernio-like lesions. To explain this, it has been proposed that these patients have very mild disease, with low viral load undetectable by PCR, or that chilblains may present later in the course of COVID-19 when viral RNA is no longer detectable.5
Most children and adolescents with the condition have a favorable outcome, with complete resolution of lesions without treatment or complications, although hyperpigmentation can occur.1,3 In some cases, supportive measures may be necessary to control pain or pruritus. In the present case, no treatment was required, with lesions spontaneously resolving.
Since children with COVID-19 are often asymptomatic, the development of pernio-like lesions should raise clinicians’ awareness of this diagnosis, helping to early identify silent carriers and prevent further transmission of the infection.
Authorship
Diana Alba - Conceptualization; Writing - original draft
Inês Cascais - Validation; Writing - review & editing
Mafalda Moreira - Validation; Writing - review & editing
Maria Céu Ribeiro - Supervision; Validation; Writing - review & editing
Jorge Abreu Ferreira - Supervision; Validation; Writing - review & editing