Case report

A 50-year-old man presented to our dermatology clinic complaining of sudden appearance of multiple wart-like lesions on his back which had occurred two months after recovery from COVID-19 infection.
According to his medical history, the patient presented with cough, fever, and dyspnea about two months prior to the appearance of his skin lesions. He was referred to a health center where a nasopharyngeal swab was taken, and his PCR test for COVID-19 was positive. In addition, bilateral patchy ground-glass infiltration was reported in his high-resolution computed tomography (HRCT) scan in favor of COVID-19 infection. The patient was then treated with acetaminophen, dexamethasone (intramuscular injection), salmeterol, and fluticasone inhaler, and his symptoms improved.
Two months after recovery from mild COVID-19 infection, several small asymptomatic pigmented verrucous papules appeared on the patient’s back. Physical examination revealed multiple rough, oval-shaped, brownish papules varying in size from 2 mm in diameter to 15×5×2 mm (Figure 1). Dermatoscopy of the lesions was also performed. Both clinical and dermoscopic findings were in favor of seborrheic keratosis (Figure 2). In order to reach a final diagnosis, a skin biopsy was requested, and microscopic examination of the biopsy specimen showed hyperkeratosis, well-defined epidermal hyperplasia, composed mainly of the proliferation of benign-looking basaloid cells and fewer squamoid cells, horn cysts, and increased melanin, mostly in the dermo-epidermal junction. The dermis showed no significant change (Figure 3). Based on the above findings, the patient was diagnosed with eruptive seborrheic keratosis.
To determine the possible cause of this eruption, the patient was further evaluated. In his past medical history, he was generally healthy before his COVID-19 infection and had no history of co-morbidities. The patient was then examined to rule out any internal malignancies. Laboratory tests revealed normal results and included a complete blood count (white blood cells 5300/mm3, red blood cells: 4.5 × 106 /mm3, platelets: 152000/mm3), liver and kidney function tests, electrolytes, prostate-specific antigen, and urine analysis. Gastrointestinal endoscopy and colonoscopy ruled out any gastrointestinal malignancy. Chest X-ray and high-resolution computed tomography (HRCT) scan revealed no malignant lesion. In addition, the patient’s abdominopelvic sonography was normal. The patient had no family history of similar skin lesions and gave no history of any chronic inflammatory skin diseases or viral conditions. Therefore, the appearance of the Leser-Trelat sign after COVID-19 infection could be regarded as a possibility in this patient.