Acne vulgaris
Acne vulgaris: Excerpt from Professional Guide to Diseases (Eighth Edition)
Acne vulgaris is an inflammatory disease of the sebaceous follicles. The prognosis is good with treatment.
Causes and incidence
The cause of acne is multifactorial, but theories regarding dietary influences appear to be groundless. Predisposing factors include heredity; hormonal contraceptives (many females experience an acne flare-up during their first few menstrual cycles after starting or discontinuing hormonal contraceptives); androgen stimulation; certain drugs, including corticosteroids, corticotropin, androgens, iodides, bromides, trimethadione, phenytoin, isoniazid, lithium, and halothane; cobalt irradiation; and hyperalimentation. Other possible factors are 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. (See What happens in acne.) Androgens stimulate sebaceous gland growth and production of sebum, which is secreted into dilated hair follicles that contain bacteria. The bacteria, usually Propionibacterium acnes and Staphylococcus epidermidis (which are normal skin flora), secrete lipase. This enzyme interacts with sebum to produce free 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.
Acne vulgaris primarily affects adolescents (usually between ages 15 and 18), 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.
Signs and symptoms
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, acne cysts or abscesses. Chronic, recurring lesions produce acne scars.
Diagnosis
Confirming diagnosis The appearance of characteristic acne lesions, especially in an adolescent patient, confirms the presence of acne vulgaris.
Treatment
Current therapy for acne includes topical and oral agents. Topical retinoic acid (tretinoin) is the treatment of choice for noninflammatory acne consisting of open and closed comedones. Benzoyl peroxide is antibacterial and is used primarily for inflammatory acne, including papules, pustules, and cysts. Topical antibiotics are effective for mild pustular and comedone acne. Tetracycline, erythromycin, clindamycin, meclocycline, and benzamycin are all available in topical forms. Systemic antibiotics, such as tetracycline, minocycline, clindamycin, erythromycin, ampicillin, cephalosporins, co-trimoxazole, and systemic retinoids may help reduce the effects of acne.
Systemic therapy consists primarily of antibiotics, usually tetracycline (which also exhibits an anti-inflammatory effect), to decrease bacterial growth until the patient is in remission; then a lower dosage is used for long-term maintenance.
Alert Tetracycline is contraindicated during pregnancy because it discolors the teeth of the fetus. Erythromycin and ampicillin are alternatives 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 keratinization. However, because of its severe adverse effects, the 16- to 20-week course of isotretinoin is limited to those with severe papulopustular or cystic acne who don’t respond to conventional therapy. Because this drug is known to cause birth defects, the manufacturer, with Food and Drug Administration approval, recommends the following precautions: pregnancy testing before dispensing; dispensing of only a 30-day supply; repeat pregnancy testing throughout the treatment period; effective contraception during treatment; and informed consent of the patient or parents regarding the drug’s adverse effects.
A serum triglyceride level should be measured before therapy with isotretinoin begins and at intervals throughout its course.
Females may benefit from the administration of estrogens to inhibit androgen activity. Improvement rarely occurs before 2 to 4 months, and exacerbations may follow its discontinuation. Unfortunately, the high estrogen doses that are required present a major risk of severe adverse effects.
Other treatments for acne vulgaris include intralesional or oral corticosteroids, vitamin A and zinc supplements, exposure to ultraviolet light (but never when a photosensitizing agent such as tretinoin is being used), cryotherapy, and surgery.
Special considerations
The main focus of care is teaching about the disorder as well as its treatment and prevention.
❑ Check the patient’s drug history because certain medications such as hormonal 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 fanatical scrubbing with soap and water. Provide written instructions regarding treatment.
❑ Instruct the patient receiving tretinoin to apply it at least 30 minutes after washing his 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 sunscreening agent. 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’s taking isotretinoin to avoid vitamin A supplements, which can worsen any adverse effects. Also, teach how to deal with the dry skin and mucous membranes that usually occur during treatment. Tell the female patient about the severe risk of teratogenicity. 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.
Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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