Prevalence of mucocutaneous manifestations in 666 patients with COVID‐19 in a field hospital in Spain: oral and palmoplantar findings

Dear Editor, Coronavirus disease 2019 (COVID‐19) has been associated with several cutaneous manifestations.^1-3 A temporary field hospital was implemented during the pandemic peak in Madrid, Spain, to attend patients with COVID‐19 who had mild‐to‐moderate pneumonia. A team of dermatologists working as medical volunteers performed a cross‐sectional study between 10 and 25 April 2020 to evaluate cutaneous findings of such patients.

A total of 666 patients with COVID‐19 fulfilled the inclusion criteria: either positive real‐time reverse‐transcription polymerase chain reaction (RT‐PCR) testing for SARS‐CoV‐2, or bilateral pneumonia. Mean age was 55·7 years; with a slight female predominance (58%). Notably, 47·1% were from Latin America.

Overall, 304 (45·7%) of our patients presented with one or more mucocutaneous manifestations. Oral cavity findings were seen in 78 cases (25·7%), including transient lingual papillitis (11·5%), glossitis with lateral indentations (6·6%) (Figure 1a), aphthous stomatitis (6·9%), glossitis with patchy depapillation (3·9%) (Figure 1b) and mucositis (3·9%). Burning sensation was reported in 5·3% of patients, and taste disturbances (dysgeusia) were commonly associated.

Figure 1

Upper panel shows COVID‐19 oral mucosa findings. (a) Glossitis with lateral indentations and anterior transient lingual papillitis due to swelling of the tongue and friction with the teeth. (b) Glossitis with patchy depapillation. Lower panel shows palmoplantar findings in patients with COVID‐19. (c) Reddish‐to‐brown acral macules with a slight desquamation on the feet of a patient. Pathology excluded racial pigmentation, showing mild‐to‐moderate lymphocytic infiltrate surrounding the blood vessels and eccrine sweat glands. (d) Acral macules on the palm of a patient with COVID‐19 with the same histopathology.

Palmoplantar involvement was observed in 121 patients (39·8%) and included diffuse desquamation in 77 (25·3%), often favouring the weight‐bearing areas, and reddish‐to‐brown acral macules on palms and soles in 46 (15·1%) (Figure 1c, d). Mild pruritus was occasionally reported. Fungal cultures of plantar desquamation performed in nine patients ruled out superficial mycoses. Histological study from the acral macules was performed in four patients, showing a mild‐to‐moderate lymphocytic infiltrate surrounding the blood vessels and eccrine sweat glands. Seven per cent of the patients reported burning sensation (erythrodysesthesia) at the beginning of the disease.

Urticaria (6·9%), rash (2·9%) and vesicular eruptions (1·6%) were observed in a minority of patients. While urticaria and rash were observed at any stage of the COVID‐19 infection, vesicular eruptions typically appeared within the first few days of symptoms. Both urticaria and vesicular eruptions appeared in younger patients than did the other mucocutaneous manifestations, with statistical significance (P = 0·024).

Prior studies^{2, 3} have found a significantly lower prevalence of COVID‐19‐associated dermatoses (20% and 7·8%, respectively). The higher prevalence in our study may be due to additional findings not previously described. Although the oral cavity is frequently involved in viral infections, glossitis or papillitis have not been described in patients with COVID‐19·⁴ However, these differences could also be due to the conditions during hospitalization including ventilation masks, for example. We hypothesize that the contagion risk while examining the oral cavity might have precluded a thorough physical examination in these patients.

Palmoplantar involvement was also a frequent finding. Some patients recalled a burning sensation and redness or swelling of the hands or feet shortly after COVID‐19 symptoms began. Erythrodysesthesia is a common complaint secondary to cancer chemotherapy that is thought to be related to direct drug toxicity and inflammation of the eccrine glands.⁵ Interestingly, several outbreaks of poxvirus‐related erythromelalgia have been reported in China. The first outbreak occurred in Wuhan in 1987, and all patients had respiratory symptoms as well as redness and swelling of the hands and feet.⁶ Also, burning sensation has been described in chilblain‐like lesions¹ and there is one self‐reported case of a physician with COVID‐19 complaining of a ‘pins and needles’ sensation in palms and soles with subsequent appearance of acral macules.

Diffuse asymptomatic palmoplantar desquamation was another common but previously unreported finding. Although it could be related to other common conditions such as tinea pedis, patients denied its prior existence and fungal infection was excluded in nine of 121 patients.

Skin rashes were relatively uncommon, being observed in 11·6% of our patients. Although a variety of rashes have been previously reported¹ both in children and adults,^{7, 8} the exact prevalence, time of onset and age specificity remains unknown. Interestingly, pseudo‐chilblains have been commonly observed in children¹ (some of them with negative RT‐PCR or serological tests) but were absent in our 666 patients, supporting the age‐specificity trend.

Our study has several limitations. Firstly, we only included patients with mild‐to‐moderate COVID‐19 pneumonia and cannot provide data on skin disease in asymptomatic patients or with more severe forms of COVID‐19. Secondly, all patients were adults, and the prevalence of mucocutaneous findings may be different in children. Thirdly, as our work was performed in a 2‐week period, we may have missed earlier or late cutaneous manifestations of COVID‐19.

In summary, almost half of patients with mild‐to‐moderate COVID‐19 admitted in a field‐hospital during a 2‐week period showed mucocutaneous findings. The oral cavity was frequently involved and deserves specific examination under appropriate circumstances to avoid contagion risk. Redness and swelling of the hands and feet, fine palmoplantar desquamation and reddish‐to‐brown macules can help us to diagnose COVID‐19 infection and should be routinely checked.

Acknowledgments

We would like to thank Dr Angela Hernandez‐Martín for her valuable comments during the preparation of this paper.

Author Contribution

Almudena Nuno‐Gonzalez: Conceptualization (lead); Data curation (lead); Formal analysis (equal); Investigation (lead); Methodology (lead); Project administration (lead); Supervision (lead); Validation (equal); Visualization (lead); Writing‐original draft (lead); Writing‐review & editing (lead). Pilar Martin‐Carrillo: Conceptualization (equal); Data curation (equal); Methodology (equal); Validation (equal); Visualization (equal); Writing‐original draft (equal). Kyrylo Magaletskyy: Investigation (equal); Methodology (equal); Validation (equal); Visualization (equal); Writing‐original draft (equal). Maria Dolores Martin‐Rios: Data curation (equal); Formal analysis (equal); Investigation (equal); Methodology (equal); Supervision (equal); Visualization (equal); Writing‐original draft (equal). Cristina Herranz Mañas: Data curation (equal); Formal analysis (equal); Investigation (equal); Visualization (equal). Jorge Artigas Almazan: Data curation (equal); Formal analysis (equal); Investigation (equal); Methodology (equal); Visualization (equal). Gonzalo Garcia Casasola: Conceptualization (equal); Formal analysis (supporting); Investigation (supporting); Methodology (equal); Resources (equal); Supervision (supporting); Validation (equal); Visualization (equal). Elena Perez Castro: Data curation (equal); Formal analysis (equal); Investigation (equal); Supervision (equal); Validation (supporting); Visualization (supporting). Angela Gallego Arenas: Data curation (equal); Formal analysis (equal); Investigation (supporting); Supervision (supporting); Validation (supporting); Visualization (supporting). Ander Mayor Ibarguren: Formal analysis (supporting); Investigation (equal); Methodology (equal); Supervision (equal); Validation (supporting); Visualization (supporting). Marta Feito Rodríguez: Conceptualization (supporting); Investigation (supporting); Methodology (equal); Supervision (supporting); Validation (supporting); Visualization (equal). Belén Lozano Masdemont: Data curation (equal); Formal analysis (supporting); Methodology (supporting); Validation (equal); Visualization (equal). Maria José Beato: Methodology (supporting); Resources (equal); Supervision (equal); Visualization (supporting). Elena Ruiz Bravo: Methodology (supporting); Resources (equal); Validation (supporting); Visualization (supporting). Paloma Oliver: Data curation (supporting); Methodology (supporting); Resources (equal); Supervision (equal); Validation (supporting); Visualization (supporting). Maria Dolores Montero Vega: Data curation (supporting); Resources (equal); Supervision (supporting); Validation (supporting); Visualization (supporting). Pedro Herranz Pinto: Conceptualization (equal); Formal analysis (equal); Investigation (equal); Methodology (equal); Project administration (equal); Resources (supporting); Supervision (equal); Validation (equal); Visualization (equal); Writing‐original draft (equal); Writing‐review & editing (supporting).