Chilblain-like lesions and COVID-19: second wave, second outbreak.

Dear Editor,

During the first phase of European epidemic of COVID‐19, a contemporary outbreak of chilblain‐like lesions (CLL) has been reported. After that, hundreds of similar cases have been described in the world. CLL typically appeared in young otherwise healthy patients with no proven SARS‐CoV‐2 infection, and most studies did not show positivity of PCR of serology. In Italy, during the trimester March–April–May we experienced the majority of cases of COVID‐19 and contemporarily of CLL. , , During summertime, a dramatic decrease of infected patients was observed, and in that context, CLL were not reported anymore. Unfortunately, a second wave of infections flooded Italy in September and Europe as well. With the fast increase of number of contagions, after a couple of months, novel cases of CLL have reappeared in Italy.

We have collected further 15 cases (Fig. 1) in different Italian regions. Patient's profile was the same as the first wave: asymptomatic adolescent (mean age: 14 years) with history of contact with positive patients, but negative swab or serology. Also, morphology of the lesions appeared identical with CLL mostly occurring on the feet (rarely hands) with erythematous–oedematous or blistering lesions. Among these patients, one had a recurrence of CLL after lesions appeared in the first wave.

Figure 1

A 14‐year‐old with chilblain‐like lesions of toes. Lesions presented 1 month prior. The patient was asymptomatic and otherwise healthy. Both serology and PCR were negative.

It seems obvious to think that if the second wave is accompanied by a second outbreak of CLL, the relationship is certain. Actually, in most patients a direct or indirect presence of the infection has not been found. This is the first description of the second wave, and cases of CLL are probably expected to increase again.

The reason of this phenomenon is still unknown, but two different hypotheses could be advanced.

The first and most accepted one supports a relationship with SARS‐CoV‐2 infection, whose contact would induce in young patients a higher innate more than cell‐mediated immune response with consequent fast clearance of antibodies and appearance of CLL. , , , , The second less likely hypothesis is due to immobility; indeed, in Italy the first outbreak was observed during the lockdown and the second outbreak is now occurring during the soft lockdown as well. Young guys are the most affected by these measures because they are not attending schools and spending most of their time sat down watching monitors or TV. The lack of mobility could create a decreased blood flow with consequent appearance of CLL. Although interesting, against this second hypothesis is that frostbite is not among the cutaneous signs observed in paraplegic or wheelchair‐immobilized patients.

We would like to share these new data about the second outbreak and need to wait what is going to happen in the next future in order to understand whether the Italian CLL will be followed by the rest of Europe.

Funding source

None.

Conflict of interest

The authors have no financial obligations or conflict of interest to declare.

Blistering detachment on the plantar surface of first toe in the same patient.