Crecimiento de la medicina racional

The Silk Road: the pathway of rational medicine

The trading route known as the Silk Road linked China, India, the Middle East and eastern Europe c.400 BC. At around this time, a growth of rational medicine appeared in Europe along with similar ideas in south India and China, so it seems likely that a two-way flow of medical ideas took place in parallel with the trade items. It can be debated whether knowledge flowed mainly from East to West or from West to East. The ‘Diagnostic Handbook’ from Mesopotamia, from 1000 BC, remained in print but between 600 and 400 BC changed radically in nature to show that disease was subject to the forces of nature and originated from the body rather than being of a divine nature.

China

Existing texts date back to at least 200 BC, but they may have originated over 2000 years before. Some original formulae are thought to be still in use today. Although there is little relationship to what western medicine considers to be an anatomicalor physiological-based system, the underlying concepts were not based on religion or spirits. Disease is seen to be based on a loss of harmony of the yin/yang system upsetting the qi (energy) and the meridians [1]. This is a generalist approach: skin disorders are considered to be manifestations of an internal problem. Sections on skin disease exist in classic works from 652 BC. Urticaria or ‘wind type concealed rash’ was considered to be due to excess lesser yin causing fluid obstruction in the skin. The ‘Yellow Emperor’s Inner Canon’ describes urticaria and eczema.

South Indian early Buddhism

The Pali scripts date back to around 400 BC and describe the work of the Buddha [2]. The Girimananda Sutra described dermatology nursing, psychodermatology, occlusion therapy for foot eczema and possible early descriptions of skin diseases including leprosy, boils/abscesses, scrofula, ringworm, scabies, pustular eruptions, plethora, fistula and sexually transmitted diseases.

The Holy Bible

The Book of Leviticus written c.450 BC gave an account of how to diagnose ‘leprosy’ – although the descriptions of skin disease in this text could include many chronic cutaneous infections including tinea infection, impetigo and infected eczema. Practical tips on the management of contagious cutaneous disease include burning clothes and isolation of those afflicted.

Greeks: the rational age

Hippocrates (c.400 BC) was known to his contemporaries as Hippocrates the Great – an accolade indeed in the age of Plato and Socrates. He was an Asclepian physician and teacher on the island of Cos. Some great ideas attributed to him may have been written by his pupils at his school over later generations, who built up a body of medical knowledge. Hippocrates’ school moved away from the magical and religious approach to medicine and adopted a method based on logic and reason. His approach was, like the Chinese, to see disease in the context of the whole patient and to see people as physical entities subject to the same laws of nature as the world. He used diet and exercise as therapies and adopted an expectant approach, not rushing to intervene. His writings on leg ulcers are relevant now: ‘In the case of an ulcer, it is not expedient to stand; more especially if the ulcer be situated in the leg; but neither, also, is it proper to sit or walk. But quiet and rest are particularly expedient …’.

Roman Empire

Galen was born in Pergamon, Turkey in 120 AD and travelled to Egypt to learn about African and Indian medicine prior to settling in Rome. He studied anatomy through the dissection of animals (not humans), but then set Hippocratic ideas into an incorrect anatomical and physiological framework. This was based on four humours that might lead to fever if in excess: yellow bile, black bile, phlegm and blood. This led to an enthusiasm for blood-letting in his followers, aiming to restore balance in those with fever or if the physician wished to prevent fever.

Galen had a powerful intellect, an overbearing personality and a gift for self-publicity and was a prolific writer. Consequently, perhaps, this theoretical basis for medicine became entrenched in Europe and the Middle East. A period of relative intellectual stagnation regarding underlying disease processes persisted for over 1500 years. This may have been partly due to religious and cultural bans on human dissection until Renaissance times.

For 500 years after Galen, a series of Greek and Roman writers defined diseases within this flawed model of basic science. Therapeutic advances were made with various herbal and mineral remedies for skin disorders. Wood tars and coal tars were described for inflammatory skin disorders, presumably eczema and psoriasis [3]. The last of the series of Greco-Roman authors was Paul of Aegina (around 700 AD) who wrote a medical encyclopaedia in seven books of which book IV concerns skin disease [4]. This may be considered the earliest dermatology textbook.