The transverse nasal crease or groove is a usually white line between the upper two-thirds and the lower third of the human nose (slightly above the cartilage tip between the bridge and nostrils). It can occur as the result of heredity, accident, or the constant rubbing or wiping of the nose, commonly referred to as the allergic salute. Occurrence
In addition to cases caused by heredity, physical injury, the transverse nasal crease is common in children and adults with chronic nasal allergies. People with allergies often use their hands to remove mucus from a runny nose or rub an itchy nose. As the hand slides upward, the tip of the nose is pressed up, thus creating the crease. Appearance
The appearance of the line depends on skin pigmentation. On lighter-skinned people, the transverse nasal crease is lighter in color than the surrounding skin, and may appear white. This is due to hypopigmentation resulting from the low level of melanin present in the damaged skin. In darker-skinned people, the line may appear darker than the surrounding skin. == References ==
They are generally found on the floor and other surfaces, until disturbed (by walking, for example). It could take somewhere between twenty minutes and two hours for dust mites to settle back down out of the air. Dust mites are a nesting species that prefer a dark, warm, and humid climate. They flourish in mattresses, bedding, upholstered furniture, and carpets. Their feces include enzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within the human body. House dust mites did not become a problem until humans began to use textiles, such as western style blankets and clothing. Furniture
Furniture with wooden or leather surfaces reduces the dust mite population. Bed linen
Hot tumble drying a bed linen for 1 hour will kill 99% of mites therein.Weekly changing the bed linen reduces the risk of exposure to dust mites.Cotton covers not covered with complete mattress covers are very likely to become colonized by bacteria and molds; they must be cleaned periodically (at least every second to third month).