Pityriasis rosea and COVID-19.

To the Editor,

We read with interest the letter by Drago et al. on the reactivation of human herpes virus 6 (HHV‐6), HHV‐7, and Epstein‐Barr virus (EBV) in a boy with coronavirus disease‐19 (COVID‐19).

We wish to report our experience on the relationship pityriasis rosea (PR)–COVID‐19. We observed two cases of typical PR, which appeared approximately 6 weeks following the first clinical manifestations of COVID‐19. The first patient was a 26‐year‐old Caucasian girl who developed, in March 2020, cough, fever (<37.8°C), severe weakness, anosmia, and dysgeusia. Laboratory examinations revealed lymphopenia (1.600 lymphocytes/mmc = 11%). Nasal swab was positive for severe acute respiratory syndrome coronavirus 2 RNA (SARS‐CoV‐2 RNA). The patient was treated only with paracetamol. Two nasal swabs were negative in April 2020. Laboratory tests confirmed lymphopenia. In May 2020, the patient developed a typical PR. The patient is currently well, except for anosmia. The second patient was a 25‐year‐old Caucasian man who developed, in July 2020, headache, weakness, drowsiness, arthralgia, myalgia, and fever (<38.2°C). Laboratory tests showed leucopenia, lymphopenia (1.300 lymphocytes/mmc = 9%), with reduced CD4+ and CD8+ T cells, and a mild increase in erythrocyte sedimentation rate. Nasal swab was positive for SARS‐CoV‐2 RNA. Chest X‐rays were negative. The patient was followed at his home and treated only with paracetamol. Three weeks later, total anti‐N SARS‐CoV‐2 immunoglobulins (electrochemiluminescence immunoassay) resulted positive (39.11). Two nasal swabs resulted negative, 4 weeks later. Lymphopenia persisted for 6 weeks when a typical PR appeared. IgG and IgM antibodies against HHV‐6 and HHV‐7 were positive. The patient was not treated.

Although literature data on the relationship PR–COVID‐19 are poor, , , , , it is possible that PR is a cutaneous manifestation related to COVID‐19. , , Although a causal relation in these cases is not assured, we would suggest the search for SARS‐CoV‐2 in patients with PR or PR‐like eruptions living in endemic areas for COVID‐19. In addition, PR may appear, as in our two patients, some weeks following the first clinical manifestations of COVID‐19. In these cases, it is possible that lymphopenia plays a role in viral reactivation. It was demonstrated that SARS‐CoV‐2 induces reactivation of other viruses, such as HHV‐6, HHV‐7, varicella zoster virus, and EBV. , , , In a Turkish study, it was observed that the number of patients with PR and Kawasaki disease increased significantly during the COVID‐19 pandemic. The authors put forward the hypothesis that this increase was related to HHV‐6 reactivation by COVID‐19.