People with psoriasis are being treated as social outcasts, survey findings show.
The Singing Detective character had psoriasis
Telephone interviews with more than 5,000 European people revealed half would not kiss, swim with or eat food prepared by someone with psoriasis.
This was despite most realising this skin condition is not contagious.
Friday 29 October is the first world psoriasis day, aimed at increasing awareness and breaking down prejudices about this common skin disease.
Taylor Nelson Sofres surveyed 5,029 people from France, German, Italy, Spain and the UK.
Most knew that it was a type of skin disease but, less than a third of those questioned knew that psoriasis was a common disorder, affecting one in every 50 people.
Nearly two in 10 people thought poor hygiene was the root cause of psoriasis, even though three-quarters correctly knew that the condition is partly inherited and partly down to environmental factors.
Many would not want to have close physical contact, such as hugging, with someone who had psoriasis, men more so than women.
Michele Corvest, founder of APLCP - Association for the Fight Against Psoriasis - said: "I was shocked to see that half of the people surveyed would refuse to kiss or hug me or eat a sandwich from my hand."
Lars Ettarp, president of the International Federation of Psoriasis Foundations behind World Psoriasis Day, said: "For the 125million people worldwide who suffer from psoriasis, life can be extremely difficult and we are still discriminated against due to the unsightly appearance of our skin.
49% would not want to kiss or hug a person with psoriasis
45% would not want to share a swimming pool with someone with psoriasis
42% would not eat food prepared by someone who had psoriasis
18% would not want to do any of these
"We want a better standard of care for people with psoriasis."
Psoriasis expert from Charles University in Prague, Professor Petr Arenberger, said psoriasis had been recognised as a skin condition since biblical times, when people with the condition were confined to leper colonies.
Although things have improved since then, he said people with psoriasis were still treated as social outcasts.
Psoriasis occurs when the skin replaces itself too quickly.
There are many different types of psoriasis.
Psoriasis usually appears as red, scaly patches that when scraped or scratched reveal fine silvery scales.
The patches may itch and feel uncomfortable. Some people develop a specific form of arthritis related to psoriasis.