Immune thrombocytopaenic purpura following COVID-19 infection masquerading as senile purpura

Description

A woman in her 80s presented to the emergency department with a 3-month history of recurrent bruising and fatigue. She exhibited no evidence of cognitive decline and denied a history of trauma. She was a non-smoker with a medical history significant for hypothyroidism and type 2 diabetes, and the absence of any anticoagulation therapy or antiplatelet regimen. At her initial presentation 3 months ago, when she had bruising, she had a non-traumatic purpura on her right anterior crural region and was overlooked as a non-specific finding that self-resolved in a few weeks. At this presentation, vital signs were stable and physical examination unremarkable with the exception of a 3–5 cm, non-palpable, non-blanching violaceous ecchymosis on the left forearm and upper arm. A representative image of the recurrent purpura is shown in figure 1. Complete blood count, as part of the fatigue evaluation, revealed an isolated thrombocytopaenia of less than 1000/μL, also confirmed in a sodium citrate tube. Subsequently, the patient was admitted for further evaluation. Blood smear analysis showed an absence of platelets, but no burr cells or schistocytes were observed (figure 2). Coagulation studies were unremarkable. Secondary aetiologies of thrombocytopaenia indicated negative results for active infections including HIV, cytomegalovirus and hepatitis C. Rheumatological workups were unremarkable including negative antinuclear antibody. Ultrasonography did not reveal splenomegaly or liver pathology. Due to the unclear aetiology of the thrombocytopaenia, her history was further reviewed in detail. One month before the appearance of the first purpura, the patient had COVID-19 with mild upper respiratory tract symptoms. On review of the overall clinical course, the patient was diagnosed with immune thrombocytopaenic purpura (ITP) given isolated thrombocytopaenia with purpura and ecchymosis, with no other identifiable cause. Treatment included transfusion of two units of platelets, glucocorticoids and a course of intravenous immunoglobulin with adequate treatment response.

Figure 1.

Non-palpable, non-blanching ecchymoses surrounded by purpura on the right anterior crural region.

Figure 2.

Peripheral blood smear showing an almost complete absence of platelets.

COVID-19-associated ITP has been reported both as a complication following natural infection and as a complication following vaccination.^{1 2} In patients with ITP following natural infection, mild thrombocytopaenia has been reported in about one-third of the cases. Although they are relatively rare, severe or life-threatening bleeding episodes have been reported.^{1 3} The onset of ITP was common within 3 weeks of the initial COVID-19 symptoms and often occurred after clinical recovery from the virus.^{1 4} In the present case, the first purpura was observed approximately 4 weeks after the initial COVID-19 symptoms, which aligns with the onset of ITP described in the literature, consistent with the diagnosis. However, non-specific senile purpura is common in older adults, and pathological purpura, including ITP, can be easily misdiagnosed or overlooked in this population.⁵ The patient was treated with glucocorticoids and intravenous immunoglobulin, as described in the literature.^{1 6} The patient responded well to the treatment. Given the severe thrombocytopaenia, this patient likely benefited from treatment and risk evaluation of haemorrhage to reduce further complications . A close follow-up was coordinated after discharge during which a stable platelet count was confirmed. When clinicians encounter older patients with unexplained purpura in the postinfectious context, reviewing the history of COVID-19 may reveal ITP as an under-recognised pathology leading to appropriate treatment and follow-up.

Learning point.

• A rare presentation of severe immune thrombocytopenic purpura (ITP) triggered by a preceding COVID-19 infection was reported, characterized by a delayed diagnosis masquerading as a non-specific purpura in an older patient.

• Non-specific senile purpura is common in older patients, making it easy to misdiagnose or overlook more serious conditions including ITP in this age group.

• When clinicians encounter older patients with unexplained purpura in the context of the pandemic, the history of COVID-19 should raise a high suspicion of ITP. Appropriate treatment and follow-up is critical to avoid further complications.

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