No antibody response in cutaneous manifestations associated with COVID-19: An observational study of 64 cases with microbiological and clinical characterization.

BACKGROUND: The microbiological diagnosis of skin lesions related to COVID-19 is not well known. OBJECTIVE: Perform a microbiological diagnosis in COVID19-related cutaneous manifestations. METHODS: A cross-sectional study was performed with 64 patients with cutaneous manifestations associated with COVID-19 who underwent serological and nasopharyngeal reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. RESULTS: Out of the 64 patients, 6 patients had positive RT-PCR, with all of them developing SARS-CoV-2 IgG and 4 of them had positive IgM + IgA. Of the 58 patients with negative RT-PCR, 8 cases had positive IgM + IgA and only one of them had IgG seroconversion. Therefore, the infection was demonstrated in 7 cases (10.9%) and was doubtful in 7 other cases (10.9%) who presented negative RT-PCR and presence of IgA + IgM without subsequent seroconversion of IgG. Fifty patients (78.1%) had negative serological tests. The most frequent cutaneous pattern was pseudo-chilblain (48.4%) followed by maculo-papular pattern (26.6%), urticarial lesions (10.9%), vesicular eruptions (6.3%) and livedoid pattern (4.7%). The maculo-papular pattern showed the highest positivity in RT-PCR (3 cases; 17.6%) and serologies (4 cases; 23.5%). Skin lesions developed after the systemic symptoms in most patients (19 cases; 61.3%). CONCLUSIONS: Microbiological confirmation tests may not be an effective diagnostic technique for COVID-related cutaneous manifestations or that attributed lesions are not related to COVID-19. Confounding factors such as adverse drug reaction, serological cross-reactions with other viruses, the low production of antibodies in asymptomatic or mild forms of COVID-19 or its rapid disappearance, increase diagnostic uncertainty.

Penile and scrotal infundibular cysts in an adolescent treated with sorafenib.

Sorafenib is a multikinase inhibitor increasingly used for the treatment of several solid tumors. Different types of keratotic lesions, such as squamous cell carcinoma, actinic keratosis, or infundibular cyst, have been reported in association with this therapy. We present a 15-year-old male diagnosed with desmoid fibromatosis who developed multiple penile and scrotal infundibular cysts while receiving treatment with sorafenib.

Pigmented purpuric dermatosis in an infant.

Pigmented purpuric dermatoses (PPDs) are a group of idiopathic, chronic, and self-resolving conditions easily recognizable in adults but extremely uncommon in infants. We present the youngest patient with PPD reported to date.

Saturday night purpura: An uncommon presentation of exercise-induced vasculitis.

Exercise-induced vasculitis (EIV) is a benign cutaneous vasculitis that affects healthy individuals. We report a case of EIV in a 15-year-old male patient with a striking clinical appearance triggered by a combination of prolonged standing and disco dancing in a warm environment. Pediatric dermatologists should be aware of this activity as a possible trigger of EIV, especially in teenagers.

Exogenous acral pigmentation induced by coleoptera: an underdiagnosed mimic of severe disease.

Acral purpura is generally a hallmark for severe internal disease. However, exogenous pigmentation related to contact with invertebrates, can induce acral purpura-like lesions. Data regarding the beetle's ability to cause skin hyperpigmentation or purpura-like lesions are scarce. We report a case of exogenous pigmentation caused by accidental contact with a darkling beetle, clinically simulating acral purpuric lesions. The history of recent drug inhalation and abnormal autoimmunity tests made this diagnosis difficult.

Pyemotes ventricosus Dermatitis: Comet-Shaped Skin Lesions after Contact with Woodworm-Infested Furniture.

A 23-year-old woman presented to our dermatology clinic for the sudden onset of pruritic lesions on her forearms and legs for the past two days ago. She had been restoring used furniture infested with woodworm. We observed many oval "comet-shaped" erythematous maculopapules with a serpiginous track on the exposed parts of her forearms and legs (Figure 1). Considering the temporal relationship and the contact with woodworm, we were able to diagnose it as Pyemotes ventricosus. We prescribed topical corticosteroids twice daily. By the 8th day, the lesions had cleared.