INTRODUCTION Acne is a universal disease among adolescents and young adults, reaching an incidence of 80% to 90%. However, it can be seen in neonates, infants and children. The term is derived from the Greek word acne, which means spring of life. The importance of acne in adolescence lies in the involvement of the most visible part of the body, the epidermis, sometimes leaving irreparable scars. There is no predominant ethnicity, but it tends to be more severe in males than in females during adolescence, and its appearance depends on several triggering factors: genetics, stress, excessive sweating and mechanical trauma. ETIOLOGY/PATHOPHYSIOGENESIS The etiology of acne is still not very clear. The inflammatory process begins in the pilosebaceous units, which consist of sebaceous glands, ducts and rudimentary hair follicles, found on the face, upper chest and upper back. In acne patients, the epidermal follicles become stretched due to abnormal keratinization under the influence of androgens. This makes the follicle more susceptible to forming a plug. Under androgenic stimulation, sebaceous glands secrete large amounts of sebum into the follicle, which becomes colonized by bacteria from the normal skin flora, including Propionibacterium acnes , a gram-positive anaerobe. These bacteria contain lipases that degrade the triglycerides in sebum, releasing fatty acids and glycerol, which triggers an intense inflammatory response, associated with that produced by the local bacterial toxins themselves. Several factors can contribute to the appearance or worsening of acne. These include: progestogenic phase of the menstrual cycle, use of androgenic contraceptives, polycystic ovary disease, excess testosterone, derivatives of gonadal or adrenal origin and propathologies present in them. Dehydroepiandrosterone sulfate is the main adrenal androgenic hormone responsible for the appearance of pubic and axillary hair, seborrhea, axillary odors, acne and adenarche or pubarche phenomena in adolescents. CLINICAL MANIFESTATIONS Acne tends to occur on the face and, to a lesser extent, on the upper back, chest and shoulders. This area corresponds to the greatest distribution of pilosebaceous units on the body. The distal extremities are always spared. According to the classification of acne, which is also used for treatment purposes, the lesion is divided into: 1. non-inflammatory (comedonal and papular); 2. inflammatory (papulopustular, pustular and nodular-cystic). The pathognomonic lesion is the comedone, which can be open or closed. The first is also called a blackhead, and is flat or slightly raised, measuring approximately 1 to 3 mm in diameter. The black part, contrary to what many laymen think, is not dirt or oxidized fat, but melanin, which comes from melanocytes, which are concentrated only at the tip of the sebaceous follicle. A closed comedone, commonly known as a whitehead, appears as a pale, slightly raised papule with a visible central pore. Blackheads generally do not become inflamed unless the pilosebaceous duct is traumatized by external forces, such as squeezing the lesions. Whitehead lesions, on the other hand, can either open their pores, resulting in melanization and the formation of blackheads, or become pustular. The danger lies in the rupture of the pustular lesions, which release free fatty acids into the surrounding tissues, resulting in an intense inflammatory reaction. This is caused by the action of polymorphonuclear leukocytes and complement cells. Erythematous papules, pustules, nodules and cysts (which are actually floating and suppurative nodules) may occur depending on the magnitude of the inflammation. Acne conglobate, seen predominantly in boys, is a severe, destructive and highly inflammatory form of acne, which may involve all types of associated lesions on the upper and back trunk. Acne fulminans is another rare and sudden form, with large ulcerated, necrotic and nodulocystic lesions, located on the chest and back, associated with systemic symptoms of toxemia. DIAGNOSIS It is basically clinical. a) Clinical history:

• initial age of onset of lesions;
• use of medications;
• activities and/or occupational exposure;
• previous dermatological diseases;
• in women: menstrual cycle;
• signs of androgenization.

b) Physical examination:

• type of injury;
• extent of involvement and severity;
• hirsutism;
• acanthosis nigricans .

c) Laboratory tests: blood tests are not routine unless there is suspicion of metabolic or neoplastic disease, such as polycystic ovary syndrome, late-onset congenital adrenal hyperplasia, and adrenal and ovarian tumors. DIFFERENTIAL DIAGNOSIS a) Folliculitis: inflammatory/infectious process, usually caused by staphylococcus; b) gram-negative folliculitis; c) rosacea; d) flat wart: non-inflammatory in nature and can affect the entire face; e) sebaceous adenoma (tuberous sclerosis); f) miliaria rubra; g) perioral dermatitis: caused by prolonged use of topical fluorinated corticosteroid therapy; h) hidradenitis suppurativa; i) Favre-Racouchout disease; j) secondary syphilis, with the presence of pustules on the face in adolescents, arranged in a nummular appearance, with satellite adenopathy. TOPICAL TREATMENT Isotretinoin is a retinoic acid that acts by increasing the mitotic activity of cells within the follicles. The cells become less cohesive, reducing the formation of microcomedones. Isotretinoin has no antimicrobial or anti-inflammatory activity. However, by reducing the number of comedones, the number of inflammatory lesions also decreases. a) Dose – creams: 0.025%, 0.05% and 0.1%; gel: 0.01%, 0.025% and 0.05%; b) application: before going to bed at night, 20 minutes after washing the face. c) side effects: erythema; dry and scaly skin, which resolves after approximately three weeks; sensitivity to the sun may occur, requiring protection with sunscreen. Benzoyl peroxide It has an effective antimicrobial effect against gram-positive microorganisms, significantly reducing the number of Propionibacteria acnes and Staphylococcus epidermidis on the skin surface , and should be a first-line therapy for moderate inflammatory acne. It often induces dry, scaly skin because it reduces the free fat on the skin surface. a) Dose: 2%, 5% and 10% gel; b) Application: once or twice a day; c) Side effects: erythema, staining of clothing and contact allergy. Topical antibiotics Topical antibiotics reduce the number of Propionibacteria acnes and also have intrinsic anti-inflammatory activity. They are very effective for moderate inflammatory acne, particularly in combination with a comedogenic agent. Three groups of broad-spectrum antibiotics are used: tetracyclines, erythromycin and clindamycin. They are indicated for all types of inflammatory acne, particularly those of moderate severity. Azelaic acid It has an antimicrobial effect and normalizes follicle keratinization. 20% cream. Other agents Agents that cause skin peeling, such as salicylic acid, in the form of a 2% to 5% cream or solution. Alpha-hydroxy acids and ultraviolet light are also local anti-acne treatment methods. SYSTEMIC TREATMENT It is instituted in severe cases, in nodular acne and in skin with many scars and a tendency to develop keloids. The duration of treatment is six to eight weeks. Antibiotics a) Tetracycline:

• frequent use as it is a less expensive treatment;
• dose: 500mg orally twice a day;
• side effects: gastrointestinal, photosensitivity, vulvovaginitis and pseudotumor cerebri;
• Do not use on individuals under 12 years of age due to tooth pigmentation age.

b) Erythromycin:

• frequent use as it is a less expensive treatment, but it induces bacterial resistance;
• dose: 500mg orally twice a day;
• side effects: gastrointestinal.

c) Doxycycline (derived from tetracycline):

• little used due to the high cost.
• dose: 100mg orally twice a day.
• for 14 days, then continue with one tablet per day for up to 90 days.

d) Minocycline:

• little used due to high cost;
• dose: 100mg orally once a day;
• Side effects: hives, blue pigmentation of the skin and mucous membranes, permanent discoloration of the teeth, autoimmune hepatitis and lupus syndrome. Use for 15 days.

e) Clindamycin:

• dose: 150mg orally once a day;
• side effect: pseudomembranous colitis.

f) Trimethoprim-sulfamethoxazole:

• limited use due to induction of hepatic necrosis and erythema multiforme.

g) Azithromycin:

• well accepted due to few side effects and convenient dosage;
• dose: 500mg orally once a day for three days; three to four cycles with a ten-day interval.

Isotretinoin It is 13-cisretinoic acid, derived from vitamin A. It is used in severe acne that is refractory to other treatments and in patients who are psychologically affected by acne. Its action is anti-keratinizing, atrophying the sebaceous glands and the inflammatory effect of acne. a) Side effects: hypervitaminosis A syndrome (dry lips, cheilitis, erythema, arthralgias, epistaxis, etc.) and teratogenicity (therefore, it should be used with extreme caution in women of childbearing age in adolescence; contraceptive control should be emphasized, as they can only become pregnant three menstrual cycles after the end of treatment); b) laboratory control: blood count, transaminases, cholesterol and triglycerides; c) dose: 0.5 to 1 mg/kg/day in two to three doses per day; d) duration of treatment: four to five months. Hormonal treatment Aims to antagonize the androgenic effects, since the sebaceous glands are androgen-dependent. Oral contraceptives with a greater antiandrogenic effect (ethinylestradiol + cyproterone) are usually used. FREQUENTLY ASKED QUESTIONS FROM ADOLESCENTS 1. What is acne? It is a skin condition that ranges from the appearance of small whitish or black spots to deep and diffuse inflammation of the skin, especially on the face, shoulders, chest and back. In these areas there are small glands that produce a certain type of fat called sebum. Acne appears when the pilosebaceous unit becomes blocked. 2. Why do adolescents have acne? During adolescence, hormonal changes occur during puberty. Some of these hormones increase the production of sebum (fat) at the level of the pilosebaceous units, a phenomenon that contributes to the formation of a local plug, which triggers the inflammatory process of acne. 3. What foods can influence the appearance of acne? No oily food causes acne, but rather the increased oiliness of the skin itself. That is why it is important to use appropriate anti-acne soaps more frequently. 4. Is there a cure for acne? There are several treatments for acne, to keep the skin acne-free and to avoid more serious consequences, such as permanent after-effects in extreme cases, those that can leave the skin covered in holes. Acne tends to disappear in late adolescence (around 20-21 years old), and can appear in women between 20 and 40 years old, during the menstrual cycle (hormonal change). 5. How can acne be prevented? The important thing is to consult your teen’s doctor or dermatologist to follow the most appropriate treatment and be persistent, because maintaining it regularly helps your teen’s skin stay as healthy as possible. Do not buy medicine at the pharmacy without knowing what you are buying. Avoid being in environments polluted with fats, such as fast food . Always use neutral soap and avoid cosmetics and sunscreens that may be too oily. Choose those labeled non-comedogenic. Never squeeze sores: contrary to what many people think, they can become inflamed and cause greater complications. 6. Does the sun improve and make pimples disappear? Does exposure to dust and dirty environments cause pimples? Excessive sun exposure is contraindicated, especially between 10 am and 4 pm. Skin hygiene is very important and should always be emphasized.