Novel outbreak of acral lesions in times of COVID‐19: a description of 74 cases from a tertiary university hospital in Spain

Since the outbreak of the novel coronavirus disease 2019 (COVID‐19), reports concerning suspicious COVID‐19 skin manifestations have been progressively increasing. Morbilliform, varicelliform or urticarial rashes were described first.¹ Later, acral erythematous or purpuric lesions were reported.²–⁵

At the Araba University Hospital in Spain, which covers a population of 340 000 people, we designed a descriptive study of 74 patients. We recruited all patients presenting with suspicious acral manifestations for COVID‐19 from 7 to 22 April 2020. The average temperature during this period was 14 °C. Patients with changes in their pharmacological drugs during the previous month were excluded. Owing to the pandemic, data on most patients reached us via teledermatology. Age, sex, medical history, occupation and clinical characteristics were recorded for each patient. The results are shown in Table 1.

Table 1.

	Result, %
Lesion morphology
EP	76.4
PM	40.54
Both EP and PM	16.21
Erosion	10.8
Swelling	16.21
Distribution
Hands	8.1
Feet	95.94
Both	4.05
Laterality
Unilateral	31.08
Bilateral	68.91
Symmetry
Symmetrical	51.35
Asymmetrical	44.59
Unknown	4.05
Symptoms
Pruritus	32.4
Pain	27
Asymptomatic	48.6
Extracutaneous manifestations
Frequency	29.6
Type
Respiratory	50
General	50
Latency period, days	16.15
COVID‐19 symptoms
Symptoms present
Cough	52.38
Fever	33.33
Asthenia/myalgia	28.57
Diarrhoea/nausea/vomiting	19
Dyspnoea	9.52
Anosmia/ageusia	4.76

EP, erythematous papules; PM, purpuric macules.

Of 74 patients, 42 (56.8%) were male. Mean age was 19.66 years (median 14.5 years, range 3–100 years). A small percentage (5.4%) were healthcare workers or had close contact with such workers, while 24.32% reported close contact with a person with confirmed or clinically diagnosed COVID‐19.

Most patients had erythematous papules (76.4%), similar to chilblains (Fig. 1), while 40.54% had purpuric macules. Nearly all patients showed foot involvement (95.94%) and the hands were affected in 8.1%. Bilateral (68.91%) and symmetrical (51.35%) were the most usual distribution patterns. The dorsa of the toes/fingers was the main affected location (74.3% on toes and 100% on fingers).

Figure 1.

Typical acral cutaneous findings suspicious for COVID‐19: erythematous chilblain‐like plaques with an asymmetrical distribution in the dorsum of toes.

Extracutaneous symptoms were found in 21 patients (29.6%), of which 50% also had clinical respiratory symptoms (cough and dyspnoea). In 66.7% of the cases, cutaneous manifestations developed after extracutaneous symptoms with a mean latency of 16.15 days. Two patients developed pneumonia (2.70%), both preceding the cutaneous symptoms.

In our area, COVID‐19 PCR, which has a sensitivity of about 70%, was performed on 17 516 people and 4649 were positive. Owing to the limited availability of resources only 11 patients in our study underwent PCR, and 1 had a positive result. Six patients underwent blood investigations (including autoimmunity), which did not show relevant alterations; this is in line with a previous report.^2.

A skin biopsy was taken from a lesion on the toe of one patient who had a negative serology test for COVID‐19, and histological examination revealed a lymphocytic perivascular and perieccrine infiltrate. Neither vascular occlusion nor intravascular thrombi were seen. Direct immunofluorescence study was negative. These findings are compatible with those previously described.², ³

The aetiology of these lesions remains unclear. A microangiopathic and inflammatory process is thought to occur.², ⁴–⁶ Alternatively, activation of complement, leading to inflammation and thrombi formation has been proposed.⁶ However, neither our case nor the others previously published have described thrombi.² More recent articles³, ⁴ have proposed a delayed antigen–antibody immunological reaction, which could explain their development in asymptomatic and paucisymptomatic patients.

Interestingly, we noticed an increase in the number of acral lesions 25 days after the start of lockdown. Conversely, last April we did not have similar lesions registered. Thus, we wonder whether some factors related to quarantine might have been involved, such as lack of sun exposure and consequent low levels of vitamin D.

We hope this paper will encourage sturdier studies. If the results validate our findings, acral cutaneous manifestations will represent a useful clue to identify COVID‐19 in asymptomatic and paucisymptomatic patients.

Acknowledgement

We wish to thank the collaboration of all our colleagues in the Dermatology Department of the Araba University Hospital, as well as the pathologists (Dr Malo‐Díez and Dr Martínez‐Aracil). We also thank the primary care physicians, physicians from the emergency department, pediatricians and other specialists from our hospital and from the primary care centres in our area who collaborated and helped us to perform this study.