<Things you should know> The correct knowledge about "acne" (1) Explanation of the causes, types, and symptoms of "acne" About acne Explanation of the causes (mechanisms) of acne [By Body Part] Acne found on areas other than the face We explain common questions and concerns about acne. Acne, commonly seen in teenagers and those in their twenties, can persist into their thirties. Leaving it untreated can worsen the condition and often leave scars. To properly care for acne, it's essential to have accurate knowledge about it. This article, supervised by a dermatologist, explains the types and causes of acne. About acne Even though we refer to it simply as "acne," there are many different types. First, let's discuss the different types of acne and their main symptoms, as well as symptoms that are very similar to acne. Types and symptoms of acne (names) Acne is medically known as "acne vulgaris." Acne is commonly found in areas with a high concentration of sebaceous glands, such as the face, chest, and back. Sebum that is not expelled clogs the pores, causing inflammation. Generally, acne begins in girls around age 12-13 and in boys around age 13-14, peaking around age 17-18 for girls and 19-21 for boys. Adolescent acne is physiological and usually disappears within 3-4 years. On the other hand, "adult acne" can also appear in people in their late 20s. Cases of acne developing in people in their 40s, 50s, and even 70s have also been reported. It is sometimes referred to as blemishes.Besides age, acne is also categorized by its condition. Whiteheads (closed comedones) These raised bumps, caused by clogged pores and waste products, are also called whiteheads or leukoconjunctivitis, and are commonly known as white pimples. Blackheads (open blisters) Also known as black comedones, these are pimples with a black tip. It is believed that the black color is caused by melanin, which is located inside the skin, coming to the surface. Red pimples (inflammatory pimples) These are whiteheads that have worsened and become inflamed. They are easily noticeable and difficult to treat. Yellow acne (pustular comedones) This is a pimple that has become infected and filled with yellow pus. Purple acne When redness persists after inflammation and progresses to hyperpigmentation, resulting in a purplish appearance or internal bleeding, it is sometimes referred to as "purple acne." Symptoms (medical conditions) that resemble acne The following symptoms and conditions are very similar to acne: boils A condition where the hair follicle and its surrounding area become inflamed and infected with pus. It can occur in areas where body hair grows. scalp eczema Seborrheic dermatitis is a condition that affects the scalp. It presents with red, itchy rashes that often scab over. It can recur seasonally. Cold sores Blisters form around the mouth. Chickenpox An infectious disease caused by the varicella virus. It causes rashes and blisters. Folliculitis An infection in which bacteria enter the hair follicle and cause inflammation. It can also occur on the scalp. Malassezia folliculitis This is caused by the proliferation of Malassezia fungus within the hair follicle. Milia These are small, white bumps often seen around the eyes. They are commonly thought to be "fatty deposits," but they are actually made of keratin. lichen pilaris When old dead skin cells accumulate around the pores and clog them, small bumps can appear over a wide area. This is commonly seen on the upper arms, legs, and back. sebaceous cyst These are benign tumors that commonly occur on the face and neck. Pressing them firmly may release a foul-smelling substance. chronic pyoderma A difficult-to-treat disease caused by bacterial infection. It commonly appears on the head and buttocks. Explanation of the causes (mechanisms) of acne What causes acne? We'll explain in detail the mechanisms behind acne formation. Common causes of acne There are various causes of acne, and hormones are one of them. During puberty, hormones begin to be secreted in large quantities, making pores more prone to clogging and leading to acne. In addition, lack of sleep is known to lead to hormonal imbalances. Since stress can easily lead to sleep deprivation, it's a good idea to have some time to relax before going to bed. In addition, excessive irritation to the skin can also cause acne. When shaving, it's important to use clean tools and shaving cream to reduce irritation. Also, makeup can clog pores and cause acne, so be sure to wash it off thoroughly. When skin becomes dry, its barrier function weakens, making it more susceptible to external stimuli. Therefore, be sure to moisturize thoroughly after shaving or washing your face. The typical mechanism of acne formation (the process leading up to the appearance of symptoms) When sebum is secreted excessively, it can clog pores. This causes sebum to accumulate in the sebaceous glands, where it can then lead to an increase in acne bacteria and inflammation. Acne tends to appear on the face because there are many sebaceous glands that secrete sebum. In other words, acne can potentially appear anywhere there are sebaceous glands. Maintain a regular lifestyle and get enough sleep to prevent acne from developing. [By Body Part] Acne found on areas other than the face While acne is most commonly seen on the face, it can also appear in other areas of the body with a high concentration of sebaceous glands. Besides the face, other areas prone to acne include the chest and back. The scalp is also a common site for acne due to its high sebum production. On the other hand, the palms of the hands and soles of the feet do not have sebaceous glands, so acne does not develop there. We'll explain common questions and concerns about acne. Finally, we'll answer your questions and concerns about acne, including the relationship between diet and acne, and how individual constitution can affect it. Does eating sweets like chocolate make you more prone to acne? Currently, there are no reports of a clear link between diet and acne, so you don't need to worry too much. Maintaining a balanced diet and eating regularly is important for healthy skin. Do elementary school children not get acne? Upon closer observation, microcomedones, the initial stages of acne, can sometimes be seen in boys and girls aged 8-9 years. Are there certain skin types that are more prone to acne? It's often thought that oily skin is prone to acne, but simply reducing sebum secretion doesn't necessarily improve acne. Adult acne, in particular, tends to appear in dry areas of the skin. Moisturizing is also important for dry areas. Is it possible for acne to spread to other people? Acne is not contagious, so it cannot be transmitted to other people. The bacteria that cause acne, Propionibacterium acnes, are part of the normal flora of the skin and are not infectious. Supervised by: Professor Tokuya OmiGraduated from Nippon Medical School Graduate School. Visiting Research Professor at Aarhus University and Visiting Professor at Nippon Medical School. Certified Specialist in Cosmetic Dermatology and Laser Treatment by the Japanese Dermatological Association. Certified Specialist in Dermatology by the Japanese Dermatological Association. Certified Specialist in Allergology by the Japanese Society of Allergology. We take care to post accurate information,Please point out any incorrect information. Please submit any comments regarding medical information here. 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