Photodermatitis (photodermatosis) — diseases caused by increased sensitivity of the skin to sunlight.
Photodermatitis manifested in the form of blisters, redness, itching and flaking of the skin that occur after exposure to the sun. Typically, lesions occur on the face, sometimes on the body, very rarely — on the hands and feet. The disease often develops when checking out of the sea, into the country with a more active, unusual for us the sun.
The people photodermatitis often called "allergic to the sun." However, as such an allergic component of solar rays not. Toxic or allergenic effects of the sun appears in the interaction of solar (ultraviolet) rays with any substances found in the skin (exogenous photodermatitis) or in the skin (endogenous photodermatitis).
The most striking example of exogenous photodermatitis is the so-called meadow dermatitis. In summer, during the flowering period, many prairie plants emit special substances — furokumariny that settle on the skin when finding a man in these parts. When exposed to UV while some sensitive people it may occur redness and blisters (vesicles and pustules). Rash accompanied by severe itching. Later in the affected areas of skin pigmentation is long.
Photodermatitis can also occur if before going onsun sensitive to it man anointed with ointment or cream, or used the perfume and deodorant. Substances belonging to the various cosmetic or perfumes, can react with ultraviolet rays and cause an allergic reaction. Such properties are, for example, eosin, which may be contained in lipstick, and para-aminobenzoic acid (PAVA), a part of some sunscreens. In addition, such action the polyunsaturated fatty acids, retinoids, bergamot oil, St. John's wort, rose, musk, sandalwood, fennel juice, parsley, boric, salicylic acid, phenol, mercury preparations.
Therefore, collecting makeup for a holiday by the sea, it is advisable to study the composition of perfumes and cosmetics, which is planned to take with you. And, far away, to postpone the one which includes the above substances.
Why do some people smoothly and beautifully tanned, even perfumed scent, while others are covered with blisters? Sometimes this is due to the presence of
Many drugs also contribute to photodermatitis. This effect have, in particular, sulfonamides, barbiturates, chlorpromazine, some antibiotics (doxycycline, tetracycline), antihistamines, some
Besides, increased skin reaction to sunlight appears when skin "Loose"
This group photodermatitis are quite rare diseases, the development of which play an important role in the violation of the immune system of the body, as well as various metabolic disorders (disturbances in the metabolism). Endogenous photodermatitis include, in particular, porphyria, xeroderma pigmentosum, solar eczema, solar pruritus, Hydroa vacciniformia (hydroelectric vaktsinoformnaya), polymorphic photodermatosis.
All of these conditions require careful attention of specialists (dermatologists, immunologists, allergists) and a thorough examination.