The main symptom of axillary odor, commonly known as fox, is the unpleasant odor emitted from the folds of the armpits, which affects the social life of patients and can lead to psychological disorders in serious cases. First, the difficulty of axillary odor treatment There are several bottlenecks in the diagnosis and treatment of axillary odor, resulting in the absence of a very satisfactory treatment method today. The first difficulty is the lack of objective indicators for judging the severity and efficacy of the disease. The unpleasant smell is a subjective symptom and is closely related to the patient’s psychological state. In order to evaluate the severity and efficacy of the patient’s condition relatively objectively, the author suggests the use of bystanders to make judgments. For example, in determining whether there is an indication for treatment, the patient’s surrounding relatives and classmates, colleagues or friends should be asked in detail whether they can smell the odor. Generally speaking, the more distant the judge is from the patient, the more objective he or she will be. When judging the efficacy of treatment, we should also try to standardize the conditions, such as requiring the patient to be in the same state to judge the severity of axillary odor. The second difficulty is the complexity of the causes of axillary odor and the number of key points that influence the smell, which makes each treatment method limited. It is currently believed that axillary odor is associated with the following factors: (1) Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus and Corynebacterium rotundum on the surface of axillary skin act on the sterile and odorless acrosomal sweat secretions to produce unpleasant odor, and studies have confirmed that enzymes produced by Corynebacterium leprae play an important regulatory role in the formation of axillary odor [1]; (2) the concentration of dihydrotestosterone in the nuclei of acrosomal sweat glands is higher than testosterone in patients with axillary odor. (2) the concentration of dihydrotestosterone in the nucleus of the parietal sweat gland is higher than that of testosterone in patients with axillary odor, and the levels of androgens and cytoplasmic sex hormone receptors in the nucleus of the parietal sweat gland are higher than in the normal population [2-3]; (3) 5α-reductase activity is higher in the parietal sweat gland, which is the only tissue that expresses 5α-reductase type I mRNA, which plays a major role in the metabolism of androgens. The third difficulty is that it is difficult to balance efficacy and avoid trauma given the location of the parietal sweat glands in the skin [4]. Second, the method of axillary odor treatment 1, non-invasive treatment: non-invasive treatment mainly refers to drug therapy. The mechanisms are: ① astringent and dry, avoiding excessive sweating; ② antibacterial and bactericidal, reducing the role of microorganisms; ③ odor masking, masking the smell of axillary odor with strong aroma. Pharmacological treatment is mostly symptomatic, with limited efficacy and short duration. This paper focuses on dermatosurgical treatment, so we will not repeat the drug treatment. 2, minimally invasive treatment: in a macro sense, minimally invasive treatment and invasive treatment are dermatosurgical treatment, their mechanism of action is almost always the destruction of top-secreting sweat glands. From the cause of axillary odor, it is easy to see that almost all the intrinsic causes are related to the top-secretory sweat gland: the top-secretory sweat gland secretions are broken down by bacteria, the top-secretory sweat gland cells have abnormal levels of sex hormones and sex hormone receptors, and the top-secretory sweat gland has high 5α- reducing enzyme activity. Therefore, destruction of the parietal sweat glands is considered to be the key to the cure of axillary odor. The parietal sweat glands are located in the middle dermis to the subcutaneous tissue layer. Histological studies have shown that the parietal sweat glands in the axillae of patients with axillary odor are more numerous, deeper and larger in diameter than in normal subjects. These characteristics of the parietal sweat glands in patients with axillary odor reveal the difficulty of treating axillary odor. The parietal sweat glands are numerous, large and deep, making them difficult to remove and prone to scarring and other complications. The parietal sweat gland opens into the hair follicle and is one of the tissue structures that make up the hair follicle unit. Since the acrocystic sweat glands are not visible, the hair becomes the target of axillary odor treatment, and it is usually believed that the axillary hair area is where the acrocystic sweat glands are densely distributed. The hair loss is also used as an objective indicator when judging the effectiveness of treatment. Minimally invasive treatments for axillary odor include electrolysis or electrocautery, microwave and radiofrequency therapy, laser therapy and botulinum toxin injections. (1) Electrolysis or electrocautery: The principle is to pierce the metal needle into the hair follicle in the direction of hair growth, and then apply the thermal effect to damage the hair follicle, thereby destroying the top secretory sweat gland. This method is simple and easy to use, with little damage and relatively inexpensive equipment required. The disadvantages are: ① time consuming and laborious, requiring insertion into each hair follicle and staying in each hair follicle for a period of time; ② it is not easy to properly grasp the depth of penetration into the skin, resulting in sometimes poor efficacy and sometimes excessive treatment resulting in hyperplastic scarring. (2) Microwave and radiofrequency treatment: It is the use of thermal effect to destroy the hair follicles, and the target is the dense area of axillary hairs. Although this technology is very convenient, but there is the same treatment depth is not easy to grasp the shortcomings of the treatment area is too large and too deep, more likely to complications; treatment range is too limited, the efficacy is greatly reduced. In addition, microwave treatment is not as targeted as electrolytic cautery, the damage to the normal tissue around the hair follicle is also relatively large, and sometimes the treatment of local inflammatory reaction is heavy. (3) Laser treatment: is a general term, there are many types of lasers, and new technologies are emerging. CO2 laser is a thermal effect laser, applied to the treatment of axillary odor relatively large side effects. There are also people using hair removal laser treatment armpit odor, the theory is based on the top secretory sweat glands and hair follicles together constitute a unit, when the hair follicles are selectively destroyed by the laser, the top secretory sweat glands will also be destroyed. The method has proven to be effective, but the treatment is often incomplete. In recent years, local injections of botulinum toxin have been reported in the literature for the treatment of axillary odor. Botulinum toxin is known to inhibit the release of acetylcholine from the presynaptic membrane at the neuromuscular junction. Studies have shown that parietal sweat glands and small sweat glands can be stimulated to secrete by cholinergic drugs, so it is hypothesized that botulinum toxin can inhibit the secretion of parietal sweat glands and other glands by inhibiting cholinergic effects. This hypothesis has been confirmed by clinical trials and case reports have appeared in academic journals. Although the number of cases is not much, and its effectiveness can only be maintained for a short period of time, but this treatment method has many advantages, such as simple and easy, less invasive, especially suitable for the treatment of odor in the vulva, apparently many surgical methods of axillary odor is not applicable to the vulva. 3, invasive treatment: surgery to destroy the local top-secreting sweat glands is considered to be the most thorough treatment of axillary odor, mainly in the elimination of odor significantly, the efficacy of maintaining a long time. However, surgery inevitably has the disadvantages of large trauma and complications, so the procedure is constantly improved to improve the efficacy and reduce the occurrence of complications. 4, traditional surgery: the initial treatment method of axillary odor surgery is the implementation of a large pike excision in the axillary hair area. The most serious problem with this procedure is the high tension of the surgical primary defect, the wound is prone to dehiscence, easy to form a contracture scar, and can seriously affect the function of the patient’s shoulder for a long time. This surgical method is rarely used now. 5.Scraping surgery style: In order to reduce the wound tension, so some people explore cutting the skin (without removing the skin), through the incision in the axillary hair area within the full subcutaneous free, and then scraped from the bottom of the skin to remove the subcutaneous tissue, and even part of the deep dermal tissue, generally speaking the scraped skin shows a purplish red color on the treatment in place. This method is still widely used, but the incision design and scraping tools are constantly being improved. Since the longer the incision, the more likely it is to form a significant scar, the length of the incision is becoming smaller and smaller, even down to 1 cm, which is also known as the micro-incision style. Today, incision shapes are linear, S-shaped, W-shaped, etc. The main purpose is to change the direction of incision tension and reduce scar formation. As far as the location of the incision is concerned, some are placed in the center of the axillary hair area, while others are placed at the upper or lower edge of the axillary hair area. In short, there are advantages and disadvantages to each incision design. The instruments used for scratching, such as the spatula, have also been improved and are becoming more convenient and smooth [6]. It is worth mentioning that Professor Wang Gaosong, one of the founders of Chinese dermatologic surgery, designed his own set of axillary scraping tools, which are still in use today. Inevitably, there are some limitations of the scratching procedure. For example, scratching is performed under non-visible conditions, so there is a possibility of poor scraping or excessive scratching resulting in flap necrosis. In addition, the unobserved bleeding will also increase the chances of postoperative hematoma formation and secondary infection. 6, liposuction treatment of axillary odor: Since the invention of liposuction expansion fluid by American dermatologists, liposuction cosmetic technology has been introduced into the field of dermatologic surgery. In recent years liposuction techniques have been used to treat axillary odor [7]. The method is to inject a tumescent solution into the axillary hair area, make a hole, insert a liposuction apparatus, and then use negative pressure to aspirate the subcutaneous fat. As mentioned earlier in patients with axillary odor, the hypertrophic parietal sweat glands can penetrate deep into the subcutaneous fat layer, so liposuction can destroy most of the parietal sweat glands and provide treatment. Recently, liposuction has also been performed using ultrasound or resonance principles. The drawback of liposuction for armpit odor is that the equipment technology is more complex, and the difference in experience and skill level of the operator leads to some differences in treatment results. 7, visual conditions to cut out the top secretion sweat gland: whether scratching or liposuction, the operator can not directly visualize the top secretion sweat gland, which makes the effectiveness of the treatment may be greatly reduced due to the operator’s inexperience. There are two types of techniques for visual excision of parietal sweat glands: (1) endoscopic techniques; and (2) flap surgical excision techniques. The former is not yet popular, although cases have been reported due to the complexity and cost of the equipment. Surgical clipping of the parietal sweat glands should be considered the mainstream technique at present, and it is developing rapidly. In the past, a large incision was often used to fully free the subcutis and flap the parietal sweat glands. Although the efficacy of this method is clear, it is often criticized due to heavy scarring, flap necrosis and high chance of hematoma formation. Incisional design has thus become the main direction of improvement of this method. Firstly, the incisions became smaller and smaller, resulting in today’s micro-incision technique; secondly, the incision shapes were designed as straight, S-shaped, W-shaped, etc., just like scratch incisions. Finally, the location and number of incisions have also been improved. Currently, the most common design is to trisect the axillary hair area, make two parallel lines of tiny incisions, and then fully free the subcutis through the two incisions, then flip the flap and trim the parietal sweat glands under visualization conditions. The efficacy of this method is very positive, but it still has the disadvantages of easy formation of hematoma and flap necrosis. The flap is likely to necrosis and the two incisions between the flap length ratio is not appropriate or excessive cut skin tissue. Third, other considerations for the treatment of axillary odor (1) patient selection criteria and exclusion criteria for treatment: the top secretory sweat glands usually develop rapidly during puberty and secretion gradually reaches its peak, so the best time for patient treatment is best after puberty, otherwise it is easy to relapse. Furthermore, the more serious the symptoms of axillary odor the better the treatment effect, so those patients with clear symptoms of axillary odor (surrounding people clearly smell the odor) and whose quality of life is significantly disturbed should be selected for treatment, but be cautious of those patients who have too high expectations of the treatment effect or who have already developed psychological barriers to axillary odor, after all, axillary odor is a subjective symptom and the efficacy is closely related to the patient’s psychological state. (2) Thoroughly develop a method of judging the efficacy of axillary odor: there is no accepted method of judging, but the requirement to judge the criteria as objective as possible is the consensus of physicians and patients. Generally speaking, the efficacy assessment includes the judgment of patients themselves, physicians and bystanders on the improvement of odor, the reduction of axillary hair and sweat in the axillary hair area. When making these judgments, the patient is required to be in a resting state, and the bathing and dressing conditions should be fixed, as well as the distance to smell the odor. In addition, seasonal climate has an effect on axillary odor, so in principle, axillary odor should be followed up for more than 1 year after treatment. Axillary odor treatment technology is still evolving, and the direction is minimally invasive and thorough.