Deliberate self-harm masquerading as psychogenic purpura: The dangers of misdiagnosis and imperative for psychiatric assessment

To the Editor

Psychogenic purpura (PP), or Gardner-Diamond syndrome, is a rare psychodermatological condition reported approximately 200 times in the published literature. PP has no established diagnostic criteria, confirmatory diagnostic tests or validated scientific explanatory model (Sridharan et al., 2019). The phenotype of PP is variable but manifests in the context of psychosocial distress. Patients present with sensation changes and localised pain preceding painful ecchymoses on extremities (Sridharan et al., 2019). Identified risk factors include young age, female gender and comorbid psychiatric disorder. Non-specific associated symptoms reportedly include panic, dissociation, functional neurological deficits, myalgia, headache, dizziness and gastrointestinal distress (Jafferany and Bhattacharya, 2015). Hypothesised mechanisms, including abnormal immunological dysregulation or erythrocyte membrane abnormality (Sridharan et al., 2019), fail to explain spontaneous remission following resolution of emotional distress.

We report an 18-year-old female admitted to a hospital’s general medical ward for workup of sudden-onset ecchymoses on bilateral legs and forearms. Symptoms arose in context of a situational crisis with associated distress, on a background of generalised anxiety. The patient reported localised burning and tingling prior to the onset of bruising, associated with patchy paraesthesia and intense pain in bilateral lower legs. Examination revealed macular ecchymoses on the thighs, lower legs and forearms. Skin lesions appeared of different ages, some with a linear morphology. Biopsy revealed extravasated dermal red blood cells. Extensive investigations for causes of bruising were unremarkable. Nerve conduction studies were normal. Paraesthesia and bruising spontaneously remitted after admission without medical intervention. Deliberate self-harm (DSH) was initially denied, so a diagnosis of PP was made. Formal psychiatric assessment subsequently elicited an undisclosed history of affect dysregulation with active and historical DSH, and dermatology revised the diagnosis from PP to ‘exogenous bruising’.

Some authors do not recommend psychiatric assessment in all cases of PP, specifying instead that a ‘consideration of a psychiatric referral’ suffices (Sridharan et al., 2019). Given the stigma associated with DSH, some patients might not divulge a relevant psychiatric history to medical teams, as highlighted by our case. Managing PP before excluding DSH, somatic symptom disorder, factitious disorder, conversion disorder or malingering might lead to serious iatrogenic harms, given previous treatments for PP include glucocorticoids, hormonal contraceptives, intravenous immunoglobulin, antibiotics, kallikrein inhibitors, therapeutic plasma exchange and anti-inflammatory medications (Sridharan et al., 2019). This correspondence seeks to highlight PP as a poorly characterised and biologically unexplained diagnosis that overlaps significantly with complex somatoform disorders. We advocate that all patients with a provisional diagnosis of PP be offered psychiatric assessment for diagnostic and management input given the side effect profiles of previous treatments.