Skin, like eyes, can provide important clues to health and aid in the diagnosis of disease. The skin is our largest organ in terms of volume. The skin protects us from pathogens entering the body, unless the skin is broken; although some pathogens, such as hookworm, can enter through bare skin, when walking barefoot in grass and coming in contact with hookworm.  Pathogens can be transferred from the mouth and nose to the skin; and to our devices, and then our skin, causing brown spots and/or pimples.

Brown spots are ubiquitous since modern cell phones; and can also occur where fingertips routinely touch, such as the upper arm. Brown spots often follow the path where a fingertip or device touched, and may be caused by bacterial, viral or fungal pathogens. Avoiding touching fingertips to the skin unless the hands are washed, and keeping devices away from the skin, can help prevent unwanted brown spots and pimples on the face, arms and body.