Diagnosing the Dermatologic Blues: Systematic Review of the Rare Conundrum, Psychogenic Purpura

BACKGROUND: Psychogenic purpura is an idiopathic psychodermatologic condition of recurrent, painful purpura precipitated by psychological stress, predominantly affecting young females. Little consensus exists on the diagnostic guidelines for this rare condition, often resulting in costly, unnecessary, and stressful investigations as well as prolonged hospital admissions. OBJECTIVE: With this first up-to-date systematic review of 134 cases of psychogenic purpura in over a decade, we aim to thoroughly investigate the diagnostic strategy and treatment regimens used in the last decade. With a sooner diagnosis, patient stress and nosocomial ecchymoses can be minimized, and treatment can be expedited. METHODS: We conducted a literature review of 4 databases (PubMed, Ovid Embase, Ovid MEDLINE, and Web of Science) on October 5, 2022 that yielded 46 full-text articles, which were reviewed and extracted by 2 independent reviewers. RESULTS: We analyzed a total of 134 cases, consisting largely of females (125/134, 93.3%) with purpura on the upper (103/134, 76.9%) or lower limbs (112/134, 83.6%). Apart from a paresthesia prodrome, patients commonly experienced headaches, malaise, and arthralgia or myalgia. Approximately 70% (95/134) of patients reported a physiological or psychological stressor or psychiatric diagnosis before the development of the purpura. Laboratory testing almost always revealed unremarkable results. The intradermal washed autoerythrocyte sensitization test was positive in 98% (42/43) of cases. Histopathology biopsy findings commonly revealed dermal erythrodiapedesis or hemorrhage (n=34) and perivascular inflammatory infiltrates (n=17). Approximately 42% (56/134) of patients received a novel psychiatric diagnosis, with depression being the most common (40/72, 56%). In both patients with and those without a novel psychiatric diagnosis, observation, counseling, treatment with antidepressants (ie, selective serotonin reuptake inhibitors), and psychotherapy (ie, cognitive behavioral therapy) prevailed in the resolution of the purpura. CONCLUSIONS: Due to the unclear etiology and infrequent presentation of this condition, it remains a diagnosis of exclusion based on clinical suspicion evaluating the presence of stressors or psychiatric comorbidities and exclusion of systemic conditions. Clinical confirmation can be sought through a positive autoerythrocyte sedimentation test, characteristic histopathology findings, and remission of purpura after psychiatric treatment.