polymorphic light eruption
Introduction
Introduction to pleomorphic sun rash Polymorphic sun rash is a kind of delayed allergic reaction to the skin caused by sunlight. The pathogenesis is unclear. The spectrum of pathogenic disease is mainly ultraviolet (UVB). Some patients except UVB, long-wave ultraviolet (VUA) And visible light can induce this disease. The onset may be related to the patient's epidermal pigment content, age, endocrine function and certain trace element deficiency (such as zinc and copper). More than the onset of spring and early summer, to young and middle-aged women. It is currently believed that there may be delayed photoallergic reactions caused by various causes. A variety of photoallages are associated with this. It has been reported that identical twin sisters can develop at the same time, which seems to be related to genetic factors. Women with this disease are prone to develop, and pregnancy may affect the process of disease. In addition, examination of patients with active disease of the disease found that blood zinc and copper decreased, and manganese increased. These trace elements are known to be involved in the process of DNA damage removal and repair. basic knowledge The proportion of illness: 0.003% Susceptible people: no special people Mode of infection: non-infectious Complications: Eczema
Cause
The cause of pleomorphic sun rash
Sunlight (35%):
Polymorphic sun rash is a kind of delayed allergic reaction to the skin caused by sunlight. The pathogenesis is unclear. The spectrum of pathogenic disease is mainly ultraviolet (UVB). Some patients except UVB, long-wave ultraviolet (VUA) And visible light can induce this disease.
Sunlight (35%):
The cause of the disease is not well understood, but the genetic and geographical environment may be important pathogenic factors, most of which are considered to be delayed allergic reactions caused by sunlight sensitization, and the immunosensitization of this disease to skin antigens caused by ultraviolet radiation. The pathogenic spectrum is mainly medium-wave ultraviolet, the process of exposure to sunlight and the amount of exposure, and the difference is very different in different patients. Some patients have a family history of photosensitivity.
Other factors (20%):
The onset may be related to the patient's epidermal pigment content, age, endocrine function and certain trace element deficiency (such as zinc and copper). More than the onset of spring and early summer, to young and middle-aged women.
Prevention
Polymorphic sun rash prevention
In the principle of avoiding light, but also often participate in outdoor activities, to receive small doses of short-term ultraviolet radiation, gradually increase the amount of light, improve the body's ability to withstand light exposure, to avoid between 10 am and 3 pm If you have to work outdoors, you should wear protective clothing, straw hats, gloves, etc.
Complication
Polymorphic sunburn complication Complications eczema
There are no special complications in this disease. Occasionally, there are pimples, eczema and so on.
Symptom
Polymorphic sun rash symptoms Common symptoms Papular scars itching skin heterochromia itching
The disease occurs in adults, mostly in the late spring and early summer season, natural healing in autumn and winter, skin lesions occur in the sun exposed parts, more common in the face and neck, rash is pleomorphic, the course of disease is about 3 to 5 Months are divided into four types according to the rash morphology.
1. A plaque-type rash is a red or dark red flaky or slightly infiltrating infiltrating plaque, about 20 to 25 mm in size. If it is severe and long-lasting, it may have peripheral telangiectasia and cutaneous heterochromia, and the rash subsides. After the pigmentation, consciously itchy, this type is more common.
2. Polymorphic erythematous rashes vary in size, with clear red or dark red edematous papules and slightly raised edges.
3. Eczema-type skin flushing, swelling, surface visible dense needles to rice-sized papules, blisters, erosion, crusting and desquamation, like eczema-like appearance, sometimes moss-like changes, consciously itchy, this type is rare.
4. The pruritic rash is erythema, the rice granules to the mung bean big papules, nodules, and the disease course can be lichen-like changes for a long time. After the regression, there is pigmentation, self-sinking and itching, this type is rare.
Examine
Examination of pleomorphic sun rash
Pathological examination showed dermal papillary edema, pale pale purple, dense lymphocytes infiltration around the superficial and deep blood vessels of the dermis, and some visible epidermal changes to sponge edema, epidermis blister and individual necrotic keratinocytes, some only dermal shallow Fire around the layer or deep blood vessels without significant edema of the nipple.
Diagnosis
Diagnosis and diagnosis of pleomorphic sun rash
diagnosis:
The relationship between the onset and sunlight is clearly defined, and the combined patients are mostly young women. The rash occurs in the exposed part, which damages the polymorphism, recurrent, and has obvious relationship with the season, which is helpful for diagnosis. The course of the disease was chronic, the spot test was negative, and the ultraviolet erythema reaction test showed an abnormal reaction. Organize biopsy if necessary.
Differential diagnosis:
The disease needs to be distinguished from eczema, pruritus, polymorphous erythema, acne-like vesicular disease, lupus erythematosus or actinic dermatitis.
