An inflammatory disease of the sebaceous follicles, acne vulgaris primarily affects adolescents, although lesions can appear as early as age 8. Although acne strikes boys more often and more severely than girls, it usually occurs in girls at an earlier age and tends to last longer, sometimes into adulthood. The prognosis is good with treatment.

Causes of acne vulgaris

Many factors may promote acne, but theories regarding dietary influences appear to be groundless. Research now centers on follicular occlusion, androgen-stimulated sebum production, and Propionibacterium acnes as possible primary causes.
Predisposing factors include heredity; oral contraceptives (many females experience an acne flare-up during their first few menses after starting or discontinuing oral contraceptives); androgen stimulation; certain drugs, including corticosteroids, corticotropin, androgens, iodides, bromides, trimethadione, phenytoin, isoniazid, lithium, and halothane; cobalt irradiation; and hyperalimentation.
Other precipitating factors include exposure to heavy oils, greases, or tars; trauma or rubbing from tight clothing; cosmetics; emotional stress; and unfavorable climate.
More is known about the pathogenesis of acne. Androgens stimulate sebaceous gland growth and production of sebum, which is secreted into dilated hair follicles that contain bacteria. The bacteria, usually P. acne'sand Staphylococcus epidermidis - which are normal skin flora-secrete lipase. This enzyme interacts with sebum to produce tree fatty acids, which provoke inflammation. Also, the hair follicles produce more keratin, which joins with the sebum to form a plug in the dilated follicle.

Signs and symptoms of acne vulgaris

The acne plug may appear as a closed comedo, or whitehead (if it doesn't protrude from the follicle and is covered by the epidermis), or as an open come­do, or blackhead (if it does protrude and isn't covered by the epidermis). The black coloration is caused by the melanin or pigment of the follicle. Rupture or leakage of an enlarged plug into the dermis produces inflammation and characteristic acne pustules, papules or, in severe forms, cysts or abscesses. Chronic, recurring lesions produce acne scars

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Diagnosis

The appearance of characteristic acne lesions, especially in an adolescent patient, confirms the presence of acne vulgaris.

Treatment of acne vulgaris

Commonly, acne is treated topically with benzoyl peroxide, clindamycin, or erythromycin antibacterial agents, alone or in combination with tretinoin (retinoic acid), a keratolytic. Benzoyl peroxide and tretinoin agents may irritate the skin.
Systemic therapy consists primarily of antibiotics, usually tetracycline, to decrease bacterial growth until the patient is in remission; then a lower dose is used for long-term maintenance. Tetracycline is contraindicated during pregnancy and childhood because it discolors developing teeth. Erythromycin is an alternative for these patients. Exacerbation of pustules or abscesses during either type of antibiotic therapy requires a culture to identifY a possible secondary bacterial infection.
Oral isotretinoin combats acne by inhibiting sebaceous gland function and abnormal keratinization. Because of its severe adverse effects, the 16- to 20­week course of isotretinoin is limited to those with severe papulopustular or cystic acne who don't respond to conventional therapy.
Females may benefit from taking birth control pills (such as Ortho Tri-Cyclen) or spironolactone because these drugs produce antiandrogenic effects. Other treatments for acne vulgaris include intralesional corticosteroid injections, exposure to ultraviolet light (but never when a photosensitizing agent, such as tretinoin, is being used), cryotherapy, and acne surgery

Special considerations
  • Check the patient's drug history because certain medications, such as some oral contraceptives, may cause an acne flare-up.
  • Try to identify predisposing factors that may be eliminated or modified.
  • Explain the causes of acne to the patient and his family. Make sure they understand that the prescribed treatment is more likely to improve acne than a strict diet and fanatic scrubbing with soap and water. Provide written instructions regarding treatment.
  • Instruct the patient receiving tretinoin to apply it at least 30 minutes after washing the face and at least 1 hour before bedtime. Warn against using it around the eyes or lips. After treatments, the skin should look pink and dry. If it appears red or starts to peel, the preparation may have to be weakened or applied less often.
  • Advise the patient to avoid exposure to sunlight or to use a sunscreen. If the prescribed regimen includes tretinoin and benzoyl peroxide, avoid skin irritation by using one preparation in the morning and the other at night.
  • Instruct the patient to take tetracycline on an empty stomach and not to take it with antacids or milk because it interacts with their metallic ions and is then poorly absorbed.
  • Tell the patient who is taking isotretinoin to avoid vitamin A supplements, which can worsen any adverse effects. Also discuss how to deal with the dry skin and mucous membranes that usually occur during treatment. Warn the female patient about the severe risk of teratogenesis. Monitor liver function and lipid levels.
  • Inform the patient that acne takes a long time to clear-even years for complete resolution. Encourage continued local skin care even after acne clears. Explain the adverse effects of all drugs.
  • Pay special attention to the patient's perception of his physical appearance, and offer emotional support.