Man in Beige Crew Neck Shirt Covering His Face
Man in Beige Crew Neck Shirt Covering His Face

Atopic dermatitis or atopic eczema is a skin rash that’s particularly common among young children but can last into adulthood, atopic refers to an allergy, dermatitis refers to the skin and itis refers to inflammation so atopic dermatitis describes skin inflammation that results from an allergy, more specifically it happens when the immune system attacks the skin causing a dry itchy rash on flexor surfaces of the body areas like the creases of the wrist, the insides of the elbows and the backs of the knees as well as exposed skin surfaces like on the face, the hands, in the feet when the immune system inappropriately starts attacking itself, we call that a hypersensitivity reaction and there are four types. Atopic dermatitis is a type 4 hypersensitivity reaction and it starts off with something in the environment called an allergen like flower pollen, the pollens are able to travel through the slightly porous skin where it gets picked up by an immune cell in the tissue, just below the immune cell is called an antigen presenting cell because it presents a bit of the allergen to a naive T helper cell activating it into a th to sell this th to cell then stimulates a nearby B cell to start producing IgE or immunoglobulin e antibodies specific to that pollen, those IgE antibodies bind to the surface of other immune cells called mast cells as well as basophils which can be found in the tissue layer just below the skin and this process is called sensitization, now let’s say there’s a second exposure to pollen that makes its way into the skin tissue, now the allergen can cross link the IgE on these sensitized cells resulting in degranulation or release of a number of pro-inflammatory molecules like histamine leukotriene x’ and proteases, the combined effect of these molecules is to cause nearby blood vessels to dilate and become leaky as well as attract even more immune cells to the area creating inflammation of the skin tissue, ultimately this inflammation makes the skin barrier more leaky potentially allowing in more of the allergen while at the same time allowing water to escape leaving the skin dry and scaly, dry skins are very itchy and scratching further damages the skin barrier worsening the process in setting up a vicious cycle of allergy mediated inflammation, dry skin and itching which characterizes atopic dermatitis occasionally, bacteria can invade the damaged skin causing even more inflammation in infants, the rash is most often on the face, in the scalp and in children.

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