As reported from the Hellenic Classical Era, hematidrosis is a rare medical cutaneous condition (International Classification of Diseases/ICD-10: L 74.8) which has rarely been noted throughout the ages. It is regarded as an eccrine sweat disorder, which is defined as the spontaneous dermatological excretion of a mixture of blood and sweat directly from non-traumatized skin. The pathological mechanism of blood oozing from the skin and mucosa remains unclear. However, it is hypothesized that dermal deficiencies can lead to blood-filled spaces, which may be exuded into follicular canals, or directly to the skin surface, demonstrating this peculiar phenomenon (1,2). As a medical term, it is composed of two Greek words ‘hema’ (blood) and ‘idrosis’ (sweating), while certain other associated terms used in the English medical literature include the words stigmata (also of Greek origin, hysterical stigmata), diapedesis (also of Greek origin, meaning jumping through), vicarious menstruation, ephidrosis cruenta (Greco-Latin origin), sudor cruentus and sudor sanguineus (Latin terms) (3). Hematidrosis, is classed as a somatic symptom disorder, almost always related to psychic imbalance, ranging from acute or chronic anxiety to fear (rivalry, scolding, punishment, bullying). Reports exist of extensive unnecessary investigations, which at times, have led towards risky therapeutic interventions (1,2,4). Thomas K. Chambers in 1861, suggested that this strange experience had triggered a ‘need to publish’ trend of case reports that otherwise may have been neglected. Nevertheless, the majority of available articles on the subject have appeared over the past decades. In Christianity, its notorious appearance was connected to the agony in the biblical historical reference on the ‘bloody tears’ of Jesus Christ in the Garden of Gethsemane (1,5).

The present study, inspired by the nature of hematidrosis itself, aimed to highlight both the hallmarks in the history of medicine, as well as the currently available scientific evidence. By searching through the archives of the literature in the past and simultaneously conducting a narrative review of the recent research, the present study aimed to provide a clearer picture and a thesaurus for this ‘marvel’ entity in dermatology.

A research strategy was developed to identify relevant literature. This included selecting key search terms and deciding on the criteria of inclusion and exclusion. Moreover, certain conditions were set that are critical to the quality and breadth of the present scoping review, framed by historical and epistemological sources, starting from their compatibility and retrospective consistency in the clinical context. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used consultatively to avoid a major quality deficit regarding the studies included (6). The key words which were used to render and describe this clinical entity were verbally similar diagnostic terms concerning their syllabic pronunciation to provide access to appropriate articles, chapters and books and various references, thus explaining the intended dual search. Key words included hemaditrosis, haematidrosis, hemathidrosis, αίµα and ιδρώτας (blood and sweat for the Greek texts), diapedesis, stigmata hysterica, sudor cruentus and sudor sanguineus (bleeding sweat and bloody sweat for the Latin texts). All terms are considered directly related to the research question. The present narrative review was based on original studies, clinical case reports and series, opinion articles, letters to the editor and review articles to investigate recent knowledge. A thorough survey was conducted in the online medical database PubMed/Medline for studies published over the past two decades until December 1, 2022. To limit the search and to set criteria, full-text articles published in the English language were only included. The eligibility of each citation was based on the title, abstract and full content of the articles considered and retrieved, taking into account the predefined admission criteria, such as methodological excellence, authorship, the relevance of the responsible correspondence author, and the quality and visibility characteristics of the biomedical journal hosting the publication. The factors that were evaluated covered the frequency of recording the clinical entity, management parameters, the time course of clinical manifestations, coexisting pathologic conditions and the socio-demographic and clinical characteristics of the patients. For the historical investigation, a bibliographic review was conducted using a documentary research methodology, applying the same key words as aforementioned. The year 1900 marked the end of the historical research. The survey included the following: i) Texts of antiquity within the online database Thesaurus Linguae Graecae (TLG) in Latin and Greek language; ii) works within Gallica Digital Library (Gallica-BnF) in the French language; and iii) books within online Google Digital Book Index (Google Books) in the English, French, German, Italian and Latin languages. Full-text availability was set as a criterion. Cases associated with religion and religious books were excluded for possible bigotry and deisidaimonía (superstition) to be avoided. On the other hand, this exclusion criterion may provoke a bias concerning cases with true hematidrosis. Thus, cases presenting hematidrosis during stigmata phenomenon were excluded from the main review; however, as they were partly connected to the symptom in study, they are being historically perused, discussed and registered independently.

Historical records unveiled relevant fragments of treatises during Greek antiquity, the case of Jesus Christ in early Christianity and 64 works with case references from the Renaissance until 1900. A summary of nine works had been included from within TLG, seven from Gallica-BnF and 57 form Google Books. Of the cases referred, 29 were in English, 13 in French, 13 in Latin, eight in German and one in Italian. Among the 64 works, 70 hematidrosis incidents were revealed. The mean age of those who suffered was 25.6 years. The time expanse for case reports was 426 years (Table I). The female sex was recorded in 39.7% of the affected individuals (Fig. 1). Articles in other languages (one in Russian, one in Czech and two in Spanish) were excluded, as well as some cases with no full texts (five works). A systematic search of the current medical literature of the past two decades retrieved 56 articles, 37 of which were eligible for all data requirements to have been included in the present review. Non-English articles, nine in total, five publications with no abstract or text available, and five overlapping publications were isolated and excluded. Among the 37 articles identified, a total of 44 cases were recorded. The mean age of the affected individuals was 15.8 years. The female sex exhibited a 74.4% dominance. The total time span was 15 years (2008-2022) (Table II). The number of articles on hematidrosis presents with a peak during the second half of the 19th century and after 2007. Until the end of 19th century, articles had appeared in Latin, Italian, German, French and English languages, with English language encompassing the majority of articles, followed by French and Latin. Over past two decades, all articles are written in English. A comparison of the bodily areas of the appearance of hematidrosis between the two eras in question is demonstrated in Fig. 1. Cases of famous individuals, 26 in total, experiencing hematidrosis under stigmata exposure are registered separately (Table III).

The phenomenon of sweat which resembles blood was coined to the observations noted in medicine by the ancient Greeks. Hematidrosis appeared as an affliction from the unbroken surface of the skin and greatly attracted the interest of scholars, medico-philosophers and theologians of antiquity. Aristotle was the first to mention bloody sweat in two fragments of his works, ‘if blood gets too wet people get very weak. It becomes like ichor (pus, coagulation disorders) and appears so that many have seen bloody sweat’ (7), and ‘Instances, indeed, are not unknown of persons who in consequence of a cachectic state have secreted sweat that resembled blood’ (8). Theophrastus the philosopher, the successor of Aristotle in the Peripatetic School also mentioned that ‘sometimes with sweat blood appears’ (9). The Greek historian, Diodorus Siculus, in his masterpiece entitled Bibliotheca Historica reported cases of individuals bitten by snakes tormented with pain and seized with a bloody sweat (10). The Pseudo-Gallenic collection of works mentioned sweat with blood into two books, ‘De Utilitate Respirationi’ (Latin text, paraphrasing the reports of Aristotle) and ‘De Humoribus Liber’ (Greek text, sweats in spring and summer produced by having blood and bile) (11). Marcus Annaeus Lucanus noted that the human body could emit humor, such as blood from various areas such as the limbs and nostrils (12). Hematidrosis was connected with acute anxiety in the case of Jesus Christ prior to his arrest and crucifixion inside the gospel of the physician and evangelist Luke, where Christ is reported to sweat large drops of blood when he was praying with agony in the garden of Gethsemane (Luke 22:44) (13). This report further enhanced curiosity as opposed to the phenomenon itself, resulting in numerous references by scholars throughout the next centuries and fanatic religious to state that they also similarly suffer. Kings, state officials, military officers and common individuals in agony under fear or hysteria were reported as cases of hematidrosis until the 19th century (14-31). A. Westphal wrote one of the first post-medieval dissertations on the subject, entitled De Sudore Sanguineo in 1775(32). The article of Jules Parrot's entitled ‘Study of bloody sweat and neuropathic hemorrhage’ in 1859 was considered in its era the most essential work on the subject. This original work attracted attention to the appearance of cutaneous hemorrhages and hematidrosis during paroxysms of a neuralgia, which was extremely severe and variously located (17,33). For some researchers, hematidrosis was classified as an entity related to hemophilia (Greek term meaning friendship for blood) (34), characterized by the suddenness of appearance with various outbreak patterns, connected sometime with the vicarious menstruation (35). It was also closely related to the central nervous paralysis and hysteria, to ecstasy, to agony, to convulsion (spasms), to hallucinations and in general in neurology disorders, reported as a rare symptom (36,37). According to the beliefs of the epoch, blood pure, or mingled with sweat could appear on the surface of the skin in the form of drops or issues from the glandurar openings (pilo-sebaceous, Meibomian, ceruminous) in tiny jets. Moreover, dermatorrhagia (bleeding from the sub-epidermic vascular network) could occur simultaneously and the condition have also been considered as a form of hyperhidrosis with fatal symptomatology (weakness, anemia, syncope and death) (38).

The most prolific complete treatise on the subject of hematidrosis was this of Ernst Ziegler in 1895, naming hematidrosis as diapedesis. Diapedesis of the blood through uninjured walls of vessels was considered as something peculiar and a different form the hemorrhage produced by ruptured ones when a rhexis (Greek term for rupture) occurs. This occasional spontaneous oozing of arterial blood from the sweat glands was studied by microscopy and was attributed to the rise of pressure in the capillaries and small veins combined with increased permeability of the vessel walls. As for the hemorrhagic diathesis (Greek term, meaning temper), this had been divided into congenital or hereditary and acquired. A large cluster of diseases could enact the provocation of hematidrosis, named scurvy, morbus maculosus Werlhof, purpura simples, purpura rheumatic, purpura haemorrhagica, melena neonatorum, septicemia, endocarditis, malignant pustule, spotted typhus, cholera, smallpox, plague, acute yellow atrophy of the liver, yellow fever, nephritis, phosphorus poisoning, snake-bites, malnutrition, irritation or paralysis of the vaso-mottor nerves, moral shock, terror, thrombosis or embolism or ligation of a vessel complicated with stagnation and many more. The female sex was most vulnerable against diapedesis. Psycho-therapy and palliative interventions were suggested (39). Geranium, a genus of 422 species of plants, was proposed to help confront hematidrosis (40). The treatise of Ziegler was published the same year with Moriz Kapozi's masterpiece Pathology and Treatment of the Disease of the Skin. However, Kapozi only mentioned the occasional spontaneous oozing of arterial blood from the sweat glands, named hematidrosis, considering it as the rarest case of cutaneous hemorrhage (41).

The terrifying nature of the hematidrosis phenomenon impressed the mind of medical observers and conquered the souls of the uneducated population to assume an almost miraculous character. Diapedesis on the forehead, hands and feet was stated to occur in religious bigots considered by fanatics as a gift of holy marks and bloody sweat of the Christ named stigmata. Those cases, following careful scientific examination, had proven to be, at least most of them, in the sphere of religion and faith or somehow fictitious. Religion enthusiasts bearing hematidrosis made their appearance from time to time mostly in the area of the Catholic church, stating the ability to reveal and confess the real work of God. Even publications were encountered in the form of Letters (famous type of text in religion). Hyperboles, such as for public demonstrations of hysteric or cataleptic poor peasant girls being visited by hundreds of wondering spectators ready to worship them and references of persons that had not slept or eaten for 8 years, compelled scientists to refer to them as simply impostors (14).

Charles T. Scott was the first to publish in PubMed in 1918 under the term haematidrosis, reporting the case of abnormal perspiration of a pink fluid on the forehead of an 11-year-old girl with a nervous temperament (42). Almost a century later, Joe E. Holoubek and Alice B. Holoubek in 1916, two devoted catholic physicians, performed an extensive literature review based upon a selection of 76 cases of Pooley's review ranging from the 17th century to 1980. They had classified all cases under subgroups according to the etiology: Systemic disease (e.g., scurvy and lupus), vicarious menstruation, physical exertion, psychological stress (repeated or unique), religious stigmatics and idiopathy (43). Moreover, 2 cases were reported during 2022 in the PubMed/MedLine database (44,45).

Hematidrosis depicts an eccrine sweat disorder, strongly characterized by one or more transient, yet recurring episodes of a spontaneously mixed fluid of sweat and blood from the intact epidermis. Although it presents a notoriously rare and fascinating condition, the prevalence and incidence of this condition remain unknown, as illustrated by the small number of cases published and the almost complete absence of case series. However, over the past two decades the number of cases and studies has increased, despite the fact that most of the cases which have been reviewed displayed a stereotypical presentation of bleeding pattern, background etiogenesis and therapeutic approach (1,4). Female patients presented the majority of the cases, mainly young between the ages of 9 to 15 years (46-52). Male patients have been less frequently reported, but are usually also at a young age (53,54) with a small number of exceptions of patients >65 years of age (55,56). The geographic distribution testifies a tendency towards the Asian region (India and Pakistan) as one of the two cases of those reported refers to the Indian population. A genetic predisposition was proposed to explain this geographic predilection (1,4).

The most common areas of appearance of the phenomenon, without being limited to these, are namely the forehead, scalp, face, eyes and ears, and secondary trunk and limbs. The majority of the cases were clinically examined and interdisciplinary observed by more than one specialized physician, as in numerous reports, there were suspicions that the symptom may be factitious (5). Moreover, in some reports, the diagnosis was based only on clinical criteria with insufficient laboratory examinations, accompanied by a misdiagnosed hypothesis of self-traumatism. However, fully clinically examined patients, undergoing histopathological examinations, is the trend observed over the past decade (57). Psychiatric disorders and severe stress have been proposed (1,58-60), while a post-traumatic appearance has been reported by 61. Yeşilova et al (61) and Mejer (62). Various areas of appearance may be noted in a multiple concurrent emergence. Οtorrhea, hematuria, epistaxis, bleeding from the intestines the oral cavity and the eyelids have also been mentioned (1,41,59,60,63). Pathology usually reveals a free medical history, and records have demonstrated no family incidents; laboratory tests of complete blood count, coagulation, immunology, renal and liver function have yielded inconclusive results (60). Dermatological evaluation have disclosed no cutaneous lesions. Histological findings following skin biopsy have ranged from congested blood vessel capillaries, extravasation of erythrocytes within the follicular lumen, leakage of red blood cells in dermis, or even just normal skin layers (1,2,43). In a case where an increased number of CD34-positive cells were observed around the eccrine sweat glands in a young female with palmar hematidrosis, the authors suggested that high pressure applied in the plantar surface of the hand (horizontal bar exercise) subsequently damaged the balance of her small blood cells, thus increasing the CD34-positive cells (64). As regards diagnosis, the following criteria have been suggested: i) testified bleeding by medical personnel; ii) red blood cell detection in the examination exudates; iii) the absence of trauma, self-injury, telangiectasias, purpura and no evidence of oozing after wiping of the area (65). Differential diagnosis included self-injury, vasculitis, connective tissue disorders (increased vascular fragility and secondary bleeding), Munchausen's by proxy syndrome, scurvy, hematomas, petechial, purpuric lesions, pseudochromhidrosis, and chromhidrosis and psychogenic purpura (5,62,66). To avoid confusion, it must be noted that chromhidrosis is characterized by the excretion of colored sweat from eccrine sweat glands, while pseudochromhidrosis sweat is colorless, later acquiring color due to its contact with chromogenic chemicals of the skin (66,67).

The patho-physiolgical mechanisms involved in the development of hematidrosis are not completely clarified. It has been calculated that half of the cases of hematidrosis remained with an undetermined causative etiology. The rupture of the small capillaries that supply sweat glands has been suggested to be the key factor of blood seepage (1). Physical fatigue and emotional stress, fear of death, school examinations, interfamily conflict and orphanage are being indicated as the most frequent triggers of this condition (1,68). Tonic seizures resolved with anti-epileptic medication may cause hematidrosis, as recorded in a 9-year-old girl by Shen et al (69) in 2015. It has been hypothesized that the hyper-reactivity of the sympathetic nervous system following a major or acute stressful event, may result in vessel vasoconstriction, altering the blood supply to the eccrine glands. In the post-stress phase as vasodilatation occurs, tinny ruptures of the nutritional vessels of the sweat glands occur and the secretion of bloody sweat droplets to the skin is implemented. A distinctive vasculitis with intra-dermal bleeding and obstructed capillaries has also been reported as the pathological basis of hematidrosis cases (70,71). Platelet factor-3 dysfunction has been also implicated (72).

Currently, there is no available treatment of choice. The benign and transient nature of the disease should be explained to the family and caregivers. Convincing the parents about the nature of the disease is mandatory for the successful management of any case. Moreover, holistic emotional support of all implicated appears to be of paramount importance (72-76). Personalized therapy and individualized interventions based on the needs of patients and caregivers are strongly recommended. The reduction of anxiety followed by the administration of benzodiazepines, such as lorazepam and diazepam has been proven efficacious (1,60). Hemostatic drugs and vitamin C are being used without any notable results. Some cases have responded to atropine transdermal patches (77), while others to adrenaline gauze wipes (73,75). The administration of β-adrenoceptor antagonists has been reported to be an effective treatment for hematidrosis by regulating sympathetic nervous system activation and reducing intense psychological excitement (4,47,78-80). Wang et al (59) in 2010 reported a complete resolution and recovery of the bleeding episodes in a 13-year old girl treated with propranolol. Oxybutynin, an anticholinergic drug, was successfully used in a 13-year-old patient (81). There are cases reporting that apart from medical personnel, patients were searching for various spiritual treatments, homeopathy and quackery (personas who fraudulently sell a product or service to supposedly cure a patient) (82).

Diapedesis from the plexus of the vessels surrounding the sweat glands has intrigued scholars and scientists; this has led to the appearance of records in medical and historical books. Shallow skepticism of the medical community denied the phenomenon for centuries, until only when it was directly observed. Apart from plausibility, failure to evolve a comprehensive explanation contributed further to its delayed acceptance. Disbelief strengthened by the fact that recorded cases were being described sporadically and in a number of cases, by completely unrelated authors (83).

A plethora of studies refer to Aristotle as the first to describe hematidrosis. That is not entirely accurate. Aristotle in his work ‘On the Parts of Animals’, truly described bloody sweat, but as a peculiarity observed in the animal kingdom, but not in humans. He only noted that it is known to exist. Some animals exude reddish fluids from the surface of the skin. This blood-colored exudation is due to color globules, and not merely to blood in the case of the hippopotamus. Flamingos secrete red fluids by their stomachs (84). The observation of domestic animals, horses and cattle reveals more representations of livestock manifesting incidents of real bloody sweat (85). There is also some confusion as regards the referrak to Galen as the pioneer to understand hematidrosis. There was an old treatise titled ‘De utilitate respiration’ bearing the same name given by Galen to one of his works. It was paraphrased by the physician, Richard Mead, in his 1749 publication on the bloody sweat of Jesus Christ. Since then, it was globally celebrated as a true work of Galen's Collection. Nevertheless, the remark was noted by some other scholars who wanted to draw additional attention by falsifying the name of the Greek majesty. Nevertheless, references for bloody sweat exist only in the pseudogalenic texts (43). To verify this fact, the authors analyzed and made a translation of 3,054 of Galens' references to blood (αίµα) and 78 to sweat (ιδρώτας) by accessing TLG, resulting in no possible much for such a case.

The Latin terms, sudor cruentus and sudor sanguineus, first appeared in 18th century medical dictionaries and indexes of the era. Hellenic-derived spellings of h[a]e [o]mat[oh/h]idrosis appeared at a later date, during 1854(43). Apart from the name of the disease, hematidrosis itself, various terms of Hellenic origin are connected to its pathology, such as H[a]emorrhage (blood outflow), hemolacria (blood in tears), otorrhea (outflow from the ears), otorrhagia (blood outflow from the ears) and epistaxis (blood drip from the nose) (86,87). Terminology only implies for an emotive entity in skin pathology. Otorrhagia appears in more articles in PubMed Central than hematidrosis. Authors worldwide have only heard about rare bleeding disorders, and yet, they believe their existence. However, this is not valid concerning cases of hematidrosis, as for many, it depicts a rather controversial theme. This, raises the question of who to choose for reader or reviewer for such an article (88). Cases such as the one reported by Hoover et al (89), of two siblings presenting hematidrosis, apart from witnessing genetic predisposition, further complicates emotions and beliefs.

In both eras investigated, during the 15th-19th century and the past 20 years, the female sex has been registered as the dominant inside scientific texts. However, the numbers of reported cases prior to 1900 are markedly lower when comparing with those reported over the past two decades. Masculine restrictions, deficiency in physical strength and limitations to intellectual developmental activities had undermined the education and intelligence of the female sex and particularly that of younger females of the humbler social casts (90). In many cases, young girls presenting hematidrosis were peregrinated for religion and profit reasons being considered as stigmatics gathering pilgrims and coin. Although a bleeding episode of a young girl may cause embarrassment, social isolation, panic and depression, the majority of those girls never attended a physician or registered as an official case (14). This fact may also explain the following: i) The difference in mean age, which was 25.6 years until 1990 and 15.8 years over the past two decades, when presumably all cases were examined by health professionals; and ii) the female sex percentage recorded until 1900 was 39.4%, while that over the past two decades increased into 74.4%. The analogy report of the anatomical areas of bloody sweat oozing through the skin demonstrates that in both eras, the scalp, forehead, face, arms, trunk and feet are the most commonly recorded regions, while the ears, eyes and mouth demonstrated considerably higher numbers in later years. The time period of the past 15 years presents the highest peak of all time concerning papers on hematidrosis, with the second half of the 19th century to follow (5,43). The second industrial revolution marked the second half of the 19th century, provoking acute social changes, while nowadays, the excessive and harmful use of technology, such as cell phones, video games, personal computers, the internet and in general, the modern way of life, greatly aggravate psychological side-effects such as anxiety, stress and depression, while the youth are often associated with emotional and behavioral issues. Increased psychic disorders increase all diseases associated, perhaps explaining the increase in the incidence of hematidrosis (91,92). Articles categorized according to the classification of hematidrosis by Holoubek and Holoubek (43) are demonstrated in Fig. 2, where psychotic disorders/stressful events constitute the main trigger factor in both eras. With the exception of the case described by Dr Hehir in India, all other references until 1900 were reported from areas of the European continent, while in the modern literature, the majority of cases are recorded in India, or in Asia. The geographic limitation of reports from Europe may be explained by the medical achievements and progress mainly due to Western European intellectual evolution through the ages, rendering this region as the major point of quotation (93). English works until 1900 comprised 45.3%, while this number increased to 80.4% over the past two 2 decades. To support geography and language results, English was cited as a universal language and globalization of the medical references.

Jesus Christ when reacting to his future and known to him torturous death, he had experienced a passionate agony, an intensified stressful juncture of emphatic emotions, which flared up as epistaxis. A number of medical writers still insist that blood fell to the ground. Richard Mead in his 1749 work was the first to notice and record that actually it was thromboi (clots of blood) which touched the earth. The reddish fluid was thick and viscous and rapidly coagulated (94,95). The Hellenic term stigma was used to reproduce the optical portraiture of the agony bleeding, crucifixion nails, thorny crown, vinegar sponge, lash and spear wounds, which had been inflicted to the palms, soles, head, chest, lips and back of Christ. Stigma in Greek antiquity indicated a bloody wound or a sign marked on a slave, while during the cultural spread of Christianity, it acquired a more mystical meaning. Nuns, priests, saints, common frauds and deep believers all experienced among other painful effects, hematidrosis. Stigmata have never been studied under the prism of a medical scientific approach until the review by Kechichian et al (96) in 2018. A cluster of symptoms received by God is reported, including painful purpura, erosions, blisters, scars and bleeding through the epidermis with intact skin layers. Hematidrosis, the symptom of interest, presents an obvious interaction between skin and psyche. In a state of ecstasy, a pure believer may endure the agony felt by his God, triggering the over-activation of the sympathetic nervous system. An acute induce of a sympathetic response of the autonomic nervous system may be held responsible for the vascular mechanisms behind hematidrosis (96). Although the conscious and voluntary fabrication or exaggeration of physical and psychological symptoms for personal gain of frauds do exist, physicians must have in mind the case of an almost ‘pure in life’ true believer who may experience in the reality of his mind, the passion of the Christ and in some cases, being canonized. Hematidrosis is a condition which remains one of gruesome fascination, but of great psychological suffering for the victim. Neurology, psychiatry, dermatology, angiology and religion must interact to explain some aspects (96-100).

Throughout the ages, a rarity in daily practice, a sporadic reference in textbooks, an enigma in medicine, a malady that may lead to extensive unnecessary laboratory tests and to hazardous therapeutic interventions, hematidrosis is a spectacular manifestation in skin pathology. It depicts a field where science, the unknown and religion intertwine. The derma, psyche and faith create a triad to explain diapedesis. For some medical personnel, the condition appears to be an inconceivable phenomenon. For others it is merely an ailment. For the Catholic church, hematidrosis in stigmata constitutes an almost divine phenomenon. As medicine without religion is a science disabled, to paraphrase the words of Einstein, the present review highlights the pathology and illustrates the necessity to believe in both, in order to comprehend the peculiarities of nature. Nevertheless, blurred etiopathogenesis, transdiagnostic variables, interdisciplinary teams of health professionals, symptomatic and inconclusive therapy and blood cells mixed with sweat are the only data that may be presumed as certain.