The human skin is the largest organ of the body with functions that include sensation, temperature regulation, water conservation, vitamin D synthesis and immunological surveillance. It is also the single most important determinant of human appearance, genetic heritage and identity. It is not surprising, therefore, that any impairment or disease of the skin has a profound impact on the general health, well-being and self-respect of an individual.
Skin diseases remain a major cause of disability worldwide; in 2013 they were responsible for 41.6 million Disability Adjusted Life Years (DALYs) globally (as a reference point, the leading cause of global DALYs over the past decade has been ischemic heart disease, responsible for 150.2 million DALYs in 2013). Diseases of the skin may be infectious, congenital, degenerative, inflammatory or cancerous and affect all ages from cradle to grave. Some of the more frequent conditions affecting the skin include atopic dermatitis predominantly affecting children, acne vulgaris posing a massive burden to teenagers, psoriasis and rosacea primality affecting the adult population and ulceration and pruritis representing debilitating conditions in the aging population.
Factors that affect the health of skin include age, genetics, environment (photodamage, air pollution) and lifestyle (smoking, stress, alcohol and nutrition). In addition, the skin’s microbiome is extremely important; the “mutualistically symbiotic” microbes that make up part of the skin barrier, together with a person’s innate immunity, combine to form a delicate balance needed to maintain healthy skin. If this balance is disturbed, the host becomes more susceptible to inflammatory diseases and cutaneous infections. It is suggested that microbiota diversity alone can predict whether skin is healthy or not.