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Foxing. Foxing is an age-related process of deterioration that causes spots and browning on old paper documents such as books, postage stamps, old paper money and certificates. The name may derive from the fox -like reddish-brown color of the stains, [1] caused by the rust chemical ferric oxide which may be involved.
Leaf spot. A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions often have a centre of necrosis (cell death). [1] Symptoms can overlap across causal ...
Liver spots (also known as age spot, solar lentigo, [1] " lentigo senilis ", [1]: 686 " old age spot ", [2] " senile freckle ") [2] are blemishes on the skin associated with aging [3] and exposure to ultraviolet radiation from the sun. [4] They range in color from light brown [5] to red or black and are located in areas most often exposed to ...
Schamberg's disease, or progressive pigmented purpuric dermatosis, is a chronic discoloration of the skin which usually affects the legs and often spreads slowly. This disease is more common in males and may occur at any age from childhood onward. This condition is observed worldwide and has nothing to do with race or ethnic background.
Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. [ 3 ][ 6 ] Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme metabolism, liver dysfunction, or biliary-tract obstruction. [ 7 ]
Cause. Mongolian spot is a congenital developmental condition—that is, one existing from birth—exclusively involving the skin. The blue colour is caused by melanocytes, melanin -containing cells, that are usually located in the surface of the skin (the epidermis), but are in the deeper region (the dermis) in the location of the spot. [6]
Brown blotch disease is a bacterial infection that affects nearly every species of mushroom. The infecting bacteria, Pseudomonas tolaasii, produces the toxin tolaasin that causes brown spots to cover the surface of the mushroom. Brown blotch disease is especially problematic on common mushroom farms, where it can spread quickly and cause huge ...
Poliosis. Poliosis circumscripta, commonly referred to as a "white forelock," is a condition characterized by localized patches of white hair due to a reduction or absence of melanin in hair follicles. Although traditionally associated with the scalp, poliosis can affect any hairy area on the body, including eyebrows, eyelashes, and beards.