I'd have described them as more of a yellowish-orange, myself.
Ninhydrin reacts with amino acids. Amino acids are all over your skin. With most of them it forms a yellowish compound; with a couple it's more of the blue-purple you're describing.
Ninhydrin reacts with amino acids present in the skin, forming a purple-colored compound. This reaction is used in forensic science to detect and visualize latent fingerprints left on surfaces.
Amino acids, specifically the primary amine group found in proteins, react with ninhydrin to produce a purple-blue color. This reaction is commonly used to detect and visualize amino acids in biological samples such as human skin.
The reasons for blood stains when sneezing could be caused by broken blood vessels. Dry skin can also cause your nose to bleed in dry weather.
Ninhydrin (2,2-dihydroxyindane-1,3-dione) is a substance intended to discover the existence of Ammonia or anything that contains Amines. When this substance reacts with these Amines a blue-purple stain will be observed. Since, the skin contains amino acid, a blue-purple stain will be noticed.
If you mean from human skin, I have not found any type of soap or hand cleaner that will remove walnut stains. But don't worry, your skin replaces itself rapidly, and in about 2 weeks the stains will fade due to new skin growth.
soap and water...
take a shower you filthey hippy
Pink stains on the skin can be a sign of various conditions, such as irritation, allergic reactions, or skin infections. They may also indicate underlying issues like eczema or psoriasis. If the stains persist or are accompanied by other symptoms, it's important to consult a healthcare professional for an accurate diagnosis and appropriate treatment.
Taking a bath does next to nothing, as the stain penetrates further into your skin than you can comfortably exfoliate. Rub the stained area(s) with a piece of at least somewhat fresh poplar wood and not only will you have the stains removed, but your skin will be very smooth for days afterward.
If you are referring to paint stains, get them off with the thinner of the paint you've been using, then wash in warm soapy water and use a hand lotion after.
Shigellosis can cause skin rash.
Silver nitrate is an antibiotic that can be corrosive to skin. Brief contact with the chemical creates brown, black, or purple stains on the skin, but increased exposure can cause burns. It is sometimes used in a lunar caustic stick for cauterizing nosebleeds and punctured varicose veins.