Long spots are annoying, and melasma is a headache, how much do you know about melasma? Let’s take a look together today!
Melasma
Melasma, also known as liver spots, is a common acquired hyperpigmentation skin disease occurring on the face, which is aggravated after sun exposure. It is common in young and middle-aged women. The course of the disease is chronic and there are no obvious conscious symptoms. The disease is seasonal, with a heavy summer and a light winter. The average optical density of the pigmented area is more than 20% of the average optical density of the face.
Typical symptoms
It occurs in women, especially during pregnancy, postpartum and oral contraceptive use. The rash is symmetrically distributed on the skin of the face, forehead, cheeks, both sides of the back of the nose, around the lips, and chin, and appears as a finger-covered to coin-sized or palm-sized irregularly shaped pale brown or dark brown sunken spots with distinct or blurred boundaries, which may fuse into a large area. No conscious symptoms, chronic, aggravated by sunlight. Some of them may fade slowly after childbirth or after stopping the use of birth control pills.
The disease is easy to diagnose according to the characteristics of yellow-brown spots on the face, more frequent in women, and no self-consciousness.
1.It occurs on the cheekbones, forehead and around the mouth of the face, and is mostly symmetrical and butterfly-shaped, so it is also called butterfly spot.
2. The initial color is like dust and dirt, and deepens with time, turning into light gray-brown or dark brown, withering and dark.
3.Variable size, clear edge of spots, smooth surface, no inflammatory reaction, no pain and itch.
4.Females who often use oral contraceptives and pregnant women will have stretch marks on their face, which is also a kind of chloasma.
5.Women with chloasma mostly have menstrual disorders, premenstrual breast swelling or chronic diseases.
6.Male chloasma patients are mostly accompanied by impotence, premature diarrhea, gastrointestinal disorders, etc.
7. Sun spots formed by frequent sun exposure are also a kind of chloasma.
Causes
Genetic susceptibility, ultraviolet radiation and changes in sex hormone level are the three important factors in the development of melasma, and vascular proliferation, skin inflammation and barrier function disorder at the pigmentation may also be involved in the occurrence of melasma.
1, genetic susceptibility is one of the main factors for the development of melasma, all races can suffer from melasma, but there are racial differences in the incidence rate, the incidence rate of dark-skinned races is higher, and patients with family history are prone to treatment resistance and delay;
2.Ultraviolet radiation in sunlight is considered to be the main factor causing the occurrence and aggravation of melasma, but it is not the only factor in the development of melasma;
3.Pregnancy, oral contraceptives and hormone replacement therapy are the most common triggering factors of melasma;
4. The number and volume of small blood vessels in the dermis at the pigmentation site increase significantly, and the expression of local vascular endothelial growth factor (VEGF) increases significantly;
5.Decrease in epidermal barrier function is related to skin aging caused by chronic ultraviolet radiation, decrease in epidermal mucin content and fatty acid metabolism disorder;
6.Decreased epidermal barrier function, which in turn leads to weakened pigment barrier function and disturbance of melanin metabolism, resulting in deposition of melanin particles in the epidermis.
Treatment methods
1.Topical treatment
① Hydroquinone and its glycoside derivatives: It is considered as the first-line treatment drug for melasma. The higher the concentration, the stronger the depigmentation effect, but the greater the skin stimulation. It is usually used once a night and can have obvious effect in 4~6 weeks after treatment, with the best effect in 6~10 weeks, and the improvement rate can reach 37%~72%.
② azelaic acid: 15%~20% cream is commonly used clinically. 2 times daily, the course of treatment is about 6 months. 1%~5% patients can have pruritus, burning sensation, pins and needles and numbness, <1% patients have erythema, dryness, desquamation, irritation, which can cause contact dermatitis.
③Fruit acid chemical peeling: Fruit acid is an effective auxiliary method for treating melasma with a concentration of <35%. The frequency of treatment is once every 2 weeks, and 4~6 times is a course of treatment.
2.Systemic treatment
①Vitamin C and vitamin E: vitamin C can stop dopa oxidation and inhibit melanin synthesis, vitamin E has strong anti-lipid peroxidation effect, and the combined application of the two is more effective. Recommended oral administration is mainly vitamin C 0.2g 3 times a day and vitamin E 0.1g once a day.
②Glutathione: Glutathione is often used in combination with vitamin C, both can be taken orally or injected intravenously.
③ Tranexamic acid: It can competitively bind the substrate (tyrosine) binding site of tyrosinase, thus inhibiting melanin synthesis, and also has the effect of inhibiting blood vessel formation and reducing erythema. It can be given orally or intravenously, oral is the most convenient and effective way of medication, small dose is effective, the usage is 250~500mg/time, 2~3 times a day, the medication takes effect in 1~2 months, the longer the treatment time, the better the efficacy, it is recommended to use continuously for more than 6 months.
3.Laser pulsed light treatment
The key to laser and intense pulsed light (IPL) treatment for melasma lies in the control of the degree of inflammatory response to the lesion, whether the laser or IPL is chosen, the parameter setting should be relatively mild. Q-switched large spot low energy or fractional mode and fractional laser have certain clinical efficacy and the degree of recurrence is mild, which can be used in clinical application, but currently it is not recommended as a means of long-term clinical maintenance treatment.
The details are as follows.
①Q modulation and fractional laser: available wavelengths: 1064, ruby 694, 1450, 1540, 1550, 1927 nm, etc. It is recommended to treat once every 2-4 weeks for 6-10 times. Clinical practice shows that Q modulated 1064 nm YAG laser with large spot and low energy or fractional mode is relatively effective, but the number of consecutive treatments should not exceed 15 times;
②IPL: It has certain effect on certain melasma, generally 1 treatment every 3~4 weeks, and no more than 5 treatments.