What are the causes of extrinsic photosensitive dermatitis?

summary

After the photosensitive substances enter the body through local or systemic medication, the corresponding clinical symptoms appear under a certain wavelength of light irradiation, which is called exogenous photosensitive dermatitis. Clinically, it can be divided into two types: light contact dermatitis and photoallergic dermatitis, among which phototoxicity and photoallergic dermatitis are the two types. What are the causes of extrinsic photosensitive dermatitis? Next, I'd like to share my views with you.

What are the causes of extrinsic photosensitive dermatitis?

The main cause of this disease is that some light sensitive substances directly contact the skin or enter the skin through oral administration, injection and other ways. Because these substances contain special molecules or chromophores that absorb light radiation, abnormal biological effects appear after exposure to sunlight, leading to the occurrence of the disease. The mechanism of action is not clear.

Sulfonamides and their derivatives, oral hypoglycemic agents (sulfabutylurea, chlorpromazine, tolbutamide), antibacterial agents (tetracyclines, griseofulvin, nalidixic acid), phenothiazines (chlorpromazine, promethazine), diuretics (chrysothiazide, hydrochlorothiazide, furosemide), antihistamines (diphenhydramine, chlorphenamine, triphenamine, etc.), salicylates (aspirin Sodium salicylate), antineoplastic drugs, contraceptives, Chinese herbal medicine, etc.

Mud snails, bamboo lice, plants such as gray vegetables, milk vetch, cabbage, amaranth, shepherd's purse, spinach, Portulaca oleracea, lettuce, Salsola, etc. Such as 8-methoxypsoralen, trimethylpsoralen, Angelicae dahuricae, etc.

matters needing attention

Be sure to stay in bed. Drinking more boiled water and infusion can accelerate the excretion of allergic drugs. Give high protein, high vitamin, high energy, easy to digest light diet. Pay attention to the airway obstruction caused by the shedding of airway mucosa. To observe whether there were symptoms of hypertension, headache and so on after using hormone. Pay attention to the heart rate, whether there is myocardial damage.