Hematohidrosis: A Rare Eccrine Disorder-Clinical Features, Diagnostic Criteria, and Therapeutic Perspectives

Hematohidrosis also written hematidrosis, or described simply as bloody sweat is an exceptionally rare condition in which blood or blood-tinged fluid is discharged from intact, non-traumatised skin or mucosa. Reports of the phenomenon reach back to antiquity, but for centuries they were entangled with religious stigmata and with suspicion of malingering, and this ambiguity long delayed acceptance of the condition as a genuine clinical entity. Modern case series describe a striking predilection for female children and adolescents, geographic clustering in Asia, and a preference for the forehead, periorbital region and ears. Episodes are usually spontaneous, recurrent, brief and self-limiting, and are most often precipitated by acute psychological stress, fear or exertion. More than a century after the disorder was first formally classified, its pathogenesis is still unresolved. The prevailing view holds that sympathetic overactivity alters the calibre of the vascular network surrounding the eccrine glands, permitting erythrocytes to enter the sweat ducts and emerge at the skin surface together with sweat. As no single laboratory test is confirmatory, the diagnosis remains one of exclusion: it rests on a witnessed episode, biochemical or microscopic proof that the discharge contains blood, and the systematic ruling out of coagulopathy, chromhidrosis, factitial disease and malingering. Treatment is empirical. Beta-adrenergic blockade with propranolol, combined with anxiolytics, antidepressants and psychological support, has yielded remission or meaningful symptom reduction in most published cases. Building on this, we organise the available options along two mechanistic axes-vascular and sudomotor and highlight anticholinergic, sudomotor-directed agents (in particular oral oxybutynin) as an emerging second-line choice, with botulinum toxin A plausible but as-yet-untested candidate. We further set out explicit diagnostic criteria and a minimum reporting dataset intended to bring greater consistency to future study of this alarming but essentially benign disorder.