Photosensitive drug eruption

Introduction to light-sensitive drug eruption A drug used for prevention, diagnosis, and treatment, which causes skin and/or mucosal damage caused by any means of entering the body, which is called a drug rash. The skin lesions that appear after the action of ultraviolet rays after administration are called light-sensitive drug eruptions. Most drugs have the potential to cause drug eruptions, including Chinese herbal medicines, but most of them are caused by more antigenicity. Commonly used are sulfonamides, tetracycline, griseofulvin, phenothiazines, nalidixic acid, diphenhydramine, desminol, quinine, isoniazid, vitamin B1, methotrexate and the like. In addition, for patients with congenital allergic diseases and patients with diseases of vital organs, the risk of drug eruption is relatively high. basic knowledge The proportion of illness: 0.006% Susceptible people: no specific population Mode of infection: non-infectious Complications: Bronchopneumonia

Light-sensitive drug eruption

Most drugs have the possibility of causing drug eruption, including Chinese herbal medicines, but most of them are caused by more antigenicity. Commonly used are sulfonamides, tetracycline, griseofulvin, phenothiazines, nalidixic acid, benzene. Hailaming, go to Minling, quinine, isoniazid, vitamin B1, methotrexate, etc. In addition, for patients with congenital allergic diseases and diseases of vital organs, the risk of drug eruption is relatively large.

Light-sensitive drug eruption prevention

Light-sensitive drug eruptions are iatrogenic diseases, so you must pay attention to:

1. Patients should be asked about the history of allergies before using the drug, avoiding the use of drugs known to be allergic or structurally similar.

2. Drugs should be targeted, try to use less sensitizing drugs, treatment should pay attention to the early symptoms of drug eruption, such as sudden itching, erythema, fever and other reactions, should immediately stop suspicious drugs, close observation and strive to determine sensitizing drugs.

Photoreceptive drug eruption Complications bronchopneumonia

Comorbidities can be associated with bronchial pneumonia or skin purulent infections, as well as with liver damage.

Symptoms of light-sensitive drug eruption Common symptoms Photoallergic blisters or bullae damage papule nodules, rash, rash, erythema (clear erythematous erythema

Skin lesions, phototoxicity and photoallergic reactions occur after UV exposure.

1. Induced drugs: sulfonamides, tetracycline, griseofulvin, phenothiazines, nalidixic acid, diphenhydramine, desminol, quinine, isoniazid, vitamin B1, methotrexate, etc.

2. Clinical manifestations: phototoxicity damage, can occur in patients taking the initial dose, 2 to 8 hours after sun exposure, erythema, edema or bullae in the exposed area, photoallergic reaction damage is 5 to 20 days after exposure Sensitization incubation period, when exposed to light, within a few minutes to 48h, the skin lesions may be erythema typhoid damage, but also may be papular, edematous plaque, nodules, blisters or eczema-like polymorphic damage, In addition to exposure, non-exposed areas can also occur, all with itching.

Light-sensitive drug eruption inspection

The disease usually has a clear history of medication. After receiving light, it can cause allergic reactions caused by decomposition of certain components in the drug. Therefore, the following main examination items are mainly carried out in clinical practice:

1. Blood routine: Because the disease is related to allergic factors, the number and proportion of eosinophils may be significantly increased, and the number of neutrophils and monocytes is relatively reduced.

2. Allergen detection: Because the disease is related to allergic factors, the body is usually an allergic constitution, so the allergen test can determine whether there are other allergic substances.

3. Biochemical items: Severe cases can cause liver and kidney function damage and electrolyte imbalance, and even liver and kidney failure, and biochemical items should be reviewed during clinical treatment.

Diagnosis of photoreceptive drug eruption

diagnosis

Diagnosis is based on clinical performance and examination.

Differential diagnosis

Need to be differentiated from the different types of drug rash:

(1) Fixed-type drug eruption is the most common type, often caused by sulfa preparations, antipyretic analgesics or barbiturates. The rash is a round or oval edematous purple-red spot with a diameter of about 1~ 2 or 3 ~ 4cm, often one, even several, the boundary is clear, the big ones have bullae on it, about 1 week after stopping the drug, the erythema subsides, leaving gray and black pigmentation spots, long-lasting, such as re-service The drug, often in a few minutes or hours, itchy at the original drug rash, followed by the same rash, and enlarged to the surrounding, so that the central color, edge flushing, blisters can also occur, new areas can also appear in recurrence The rash, with the increase in the number of recurrences, the number of rashes can also increase, the damage can occur in any part, but more common in the lips, mouth, glans, anus and other skin and mucous membrane junctions, the back of the hands and feet and the trunk often occur, can be When the hair or phoenix is involved, it occurs in the wrinkle mucosa and is easy to smash, causing pain. It usually disappears after 7 to 10 days. If it has ulcerated, it will heal slowly, and the severe one may be accompanied by fever.

(2) Urticaria-type drug eruption is more common, mostly caused by penicillin, serum products (such as tetanus or diphtheria antitoxin), furazolidone and salicylate. The symptoms are similar to those of acute urticaria, and may be accompanied by serum-like symptoms. Such as fever, joint pain, swollen lymph nodes, angioedema and even proteinuria, if the sensitizing drug is excreted very slowly or because of constant exposure to micro-allergens in life or work (such as medical staff allergic to penicillin, pharmaceutical factory workers Some drugs are allergic) and can be expressed as chronic measles.

(3) Measles-like or scarlet-like fever-like drug eruption is more common, mostly caused by antipyretic and analgesic drugs, barbiturates, penicillin, streptomycin and sulfonamides. The incidence is sudden, often accompanied by systemic symptoms such as chills and fever. Measles-like drug eruption is scattered or dense, red, cap needle to large grain rash or maculopapular rash, symmetric distribution, can spread the whole body, with a trunk more, similar to measles, severe cases may be associated with small bleeding points, scarlet fever From the beginning of the drug rash, it is a small piece of erythema. It develops from the face, neck, upper limbs and trunk. It can spread throughout the body within 2 to 3 days and fuse with each other. When it reaches the climax, the whole body is covered with erythema, the limbs are swollen, and it resembles a scarlet hot rash. The wrinkles and the flexion of the extremities are more obvious. The rash of this type of drug eruption is distinct, but the systemic symptoms are milder than measles and scarlet fever. There are no other symptoms of measles or scarlet fever. The number of white blood cells can be increased. Over-the-normal, 1 to 2 weeks after stopping the drug, the condition gradually decreased, the body temperature gradually decreased, followed by sputum or large piece of desquamation, the course of the disease is generally shorter, but if not found in time The cause and withdrawal of the drug can be developed to a severe drug rash.

(4) Eczema-type drug eruptions are mostly caused by topical sulfa or antibiotic ointment causing contact dermatitis, which increases skin sensitivity. Later, taking the same or similar chemical structure, it can cause this type of drug eruption. Its form is miliary size papules. And herpes herpes, often fused into a piece, generalized body, may have erosive exudate, but few systemic symptoms such as chills, fever, gradually improved after stopping the drug, to penicillin, streptomycin, sulfonamides, amalgam and quinine Ning et al. caused more people.

(5) Polymorphic erythema type drug eruption is often caused by sulfonamides, barbiturates and antipyretic analgesics. The clinical manifestations are similar to polymorphic erythema. The lesions are round or oval edematous erythema of pea to broad bean, papules. The center is purple-red, or has blisters. The boundary is clear. It is symmetrically distributed on the extremities of the extremities. The trunk, mouth and lips have itching sensation. In severe cases, it can be in the mouth, nostrils, eyes, anus, external genitalia and general body. Bullae and erosion, severe pain, may be associated with high fever, liver and kidney dysfunction and pneumonia, etc., the disease is sinister, known as severe polymorphic erythematous drug eruption.

(6) Astragalus-type drug eruption This type of drug eruption can be caused by barbiturate, methyl propylamine (metholamine), oral diuretics, neomycin, quinine, etc., thrombocytopenic purpura or III by type II allergy Type allergic reaction causes inflammation of the capillaries and produces purpura. In the light, the lower legs have red spots or ecchymoses, scattered or densely distributed, and some may slightly bulge. The severe limbs may be involved, even mucosal hemorrhage, anemia, etc. Sometimes small blisters can occur with the wheal or center.

(7) Bullous epidermolysis drug eruption is a serious drug eruption, often caused by sulfonamides, antipyretic analgesics (salicylic acid, phenylbutazone, aminopyrine, etc.), antibiotics, barbiturates, etc. Rapid onset, severe symptoms of systemic poisoning, high fever, fatigue, sore throat, vomiting, diarrhea and other symptoms, skin lesions are diffuse purplish red or dark red patches, often starting in the sputum and groin, quickly spread throughout the body, touch Significant pain, immediately in the erythema, the size of the blistering blister, a little smashed into a smashed surface, or the formation of a large area of epidermal necrolysis, Nie's sign positive, necrotic epidermis gray-red over the erosion surface Leaves painful peeling surface, like superficial second degree burns, mouth, buccal mucosa, conjunctiva, respiratory tract, gastrointestinal mucosa can also be eroded, ulcers, some cases start with polymorphous erythema or fixed drug eruption, very It is necessary to stop the drug and rescue immediately. In severe cases, it is often caused by secondary infection, liver and kidney dysfunction, electrolyte imbalance or visceral hemorrhage, proteinuria or even azotemia.

(8) Exfoliative dermatitis drug eruption is a serious drug eruption, mostly caused by barbiturates, sulfonamides, phenytoin, phenylbutazone, sodium salicylate, penicillin, streptomycin, etc. Most cases are after long-term use. Occurred, the first onset of the incubation period of about 20 days, some cases are based on the drug eruption, continue to use drugs, acute onset, often accompanied by high fever, chills, skin lesions initially measles-like or scarlet fever, in development In the process, it gradually intensifies and merges into diffuse redness and swelling of the whole body, especially on the face and hands and feet. It can have erosion, herpes or blister, and the effusion and sputum after rupture, until about 2 weeks, the body skin desquamation is scaly or Deciduous, hands and feet are peeled off in gloves or socks, after the hair, finger (toe) can fall off (healing can be regenerated), lips and oral mucosa flushing, swelling or blisters and erosion, affecting eating, conjunctival congestion, Edema, photophobia, increased secretion, corneal ulcer can occur when heavy, superficial lymph nodes often swollen, may be associated with bronchial pneumonia, toxic hepatitis, white blood cell count significantly increased or decreased, even fine Lack, if not promptly disabled sensitizing drugs, corticosteroids hormone therapy, skin exfoliation sustainable 2 to 3 months or longer, severe due to systemic failure or secondary infection and death.

(9) Acne-like drug eruption (acniform eruption) is caused by long-term use of iodine, bromine, corticosteroid preparation, contraceptive and isoniazid. The incubation period is longer, which is characterized by acne-like rash, which is more common in the face and chest and back. Slow development, generally no systemic symptoms, long-term use of bromine agents can develop into granulomatous lesions.

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