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Overview of polymorphic solar rash disease

Polymorphic solar eruption is a recurrent chronic multiple photosensitive dermatosis.

Etiology and pathology of polymorphic solar eruption

etiology

The cause of the disease is not very clear, but heredity and geographical environment may be important pathogenic factors. Most people think that it is a delayed allergic reaction caused by sunlight sensitization. The immune sensitivity of this disease to skin antigens changed by ultraviolet radiation. Its pathogenic spectrum is mainly UVB. The sun exposure process and exposure of different patients vary greatly. Some patients have a family history of photosensitivity.

pathological change

Dermal papillae edema, pale and purplish, with dense lymphocyte infiltration around superficial and deep dermis blood vessels, some epidermis changes into spongy edema, blisters and individual necrotic keratinocytes in epidermis, and some only have fire around superficial or deep dermis blood vessels, without obvious papillae edema.

Clinical manifestations of polymorphic solar eruption

The disease occurs in adults, mostly in late spring and early summer, and naturally recovers in autumn and winter. Skin lesions often occur in parts exposed to the sun, especially on the face and neck. The rash is polymorphic and the course of disease is about 3 ~ 5 months. According to the shape of the rash, it can be divided into four types.

1. Plaque-type rash is a red or dark red flaky or slightly raised infiltrating plaque with a size of about 20 ~ 25mm. If it is serious and lasts for a long time, peripheral telangiectasia and abnormal skin color changes may occur. Pigmentation still exists after the rash subsides. Feel itchy. This type is very common.

2. Erythema multiforme rash is a red or dark red edematous papule with different sizes, clear boundaries and slightly raised edges.

3. Eczema-type skin is flushed and swollen, with pimples, blisters, erosion, scabbing and desquamation on the surface, which look like eczema, sometimes lichen-like, and consciously itch. This type is rare.

4. Itching rash is erythema, papules and nodules the size of rice grains to mung beans. The course of the disease may be lichenoid. There is still pigmentation after regression. Self-sinking and itching. This type is rare.

Diagnosis and differential diagnosis of polymorphic solar eruption

It is not difficult to diagnose according to the medical history, frequent seasons, chronic process and abnormal reaction of ultraviolet erythema reaction test. This disease should be differentiated from the following diseases:

1. The occurrence of eczema lesions has nothing to do with irradiation and season.

2. Erythema multiforme is more common in hands and feet. If there is a typical iris-like erythema, it is easier to distinguish, and the onset has nothing to do with light.

3. Lupus erythematosus rash is persistent erythema, with keratinized phosphorus chips on the surface, enlarged hair follicle mouth, atrophic scar and telangiectasia.

4. Neurodermatitis papules are flat and conform to dermatoglyphics, which has nothing to do with light and has no seasonal influence.

Treatment of polymorphic solar eruption

1. Before going out for local treatment, you can apply 15% zinc oxide ointment, 5% titanium dioxide cream, 4% benzophenone lotion or cream, dihydroxyacetone naphthoquinone lotion, corticosteroid cream, etc. 2 ~ 3 times a day.

2. Systematic therapy

(1) 2 ~ 4mg； of antihistamine cyproheptadine; Chlorpheniramine 4 ~ 8 mg once a day. Xisi10 mg; ; Kemineng 10mg orally once a day.

(2) Take chloroquine 250mg orally, 2-3 times a day. After the disease is controlled, it will be reduced to 1-2 weeks a day, and the dose will be given once every 2-4 days. Hydroxychloroquine sulfate 100mg orally daily 1 time. Pay attention to its side effects during taking the medicine, and the latter has less side effects than the former.

(3) Corticosteroid hormone is used for severe rash, especially eczema-like hydrocarbon rash. Prednisone is taken orally 30 ~ 40 mg a day, and gradually reduced to withdrawal after one week of disease control.

(4) Azathioprine is effective for patients with severe light sensitive person and eczema-like changes. It has been reported that azathioprine has successfully treated severe polymorphic solar eruption, but the author thinks that the drug is not suitable for most patients, and it is only used as short-term interval treatment for patients of non-reproductive age who have severe polymorphic solar eruption and have no response to other treatments. The dose is 50mg, twice a day, and the remission usually takes 2 ~ 4 months. A few can stop taking drugs after 6 ~ 8 months. White blood cells, platelets and liver function should be checked regularly during medication.

3. Photochemical therapy 8- methoxypsoralen and long-wave ultraviolet (PUVA) irradiation are effective for active lesions. Oral administration of 8- methoxypsoralen 20mg in the first 2 hours, and PUVA irradiation should start with the minimum phototoxicity or 1 Joule. Irradiation in late spring and early summer also has preventive effect.

4. The principle of treating rheumatism in TCM is to dispel wind and clear heat, and the prescription can be modified with Fang Jing Decoction. Blood-heat type is mainly cold serum heat, and Xiaofeng decoction is the prescription. Eczema can be changed by Longdan Xiegan Decoction. Danzhi Xiaoyao Powder combined with Taohong Siwu Decoction can correct the changes of prurigo.

Prediction and prevention of polymorphic solar burst

Take the principle of avoiding light, but often take part in outdoor activities and receive small doses of ultraviolet radiation for a short time, gradually increase the amount of light and improve the body's tolerance to light radiation. 10 avoid the sun from morning to 3 pm. Those who have to work outdoors should wear protective clothing, straw hats, gloves, etc.