Acne: Pathophysiology and Treatment

Acne: Pathophysiology, Treatment, and Considerations

• Prevalence: Acne is the most common dermatologic condition, affecting 85% of teenagers and often persisting into adulthood. It is typically more prevalent and severe in males.
• Onset: Usually begins during puberty due to increased androgen production.
• Location: Typically develops on the face, neck, chest, shoulders, and back.
• Mild Acne: Characterized by open comedones (blackheads) and closed comedones (whiteheads). Open comedones form when sebum and keratin combine to create a plug in the pore (oxidation of sebum causing a black appearance). Closed comedones form when pores become blocked by sebum and scales beneath the skin's surface.
• Severe Acne: Characterized by abscesses and inflammatory cysts. Increased sebum production and rapid turnover of follicular epithelial cells block pores. The presence of propionibacterium acnes (a microbe) which converts sebum into irritant fatty acids, and releases chemotactic factors promoting inflammation, intensifies symptoms.

Acne Treatment

• Non-pharmacologic: Gentle, non-irritant cleansing soaps can reduce surface oiliness. Avoid harsh scrubbing or abrasives. Avoid oil-based makeup or moisturizers. Comedo extraction, dermabrasion, etc., may be used in some cases, but dietary changes will not improve acne.
• Pharmacologic:
  • Topical: Topical antibiotics (benzoyl peroxide, clindamycin, erythromycin, dapsone) and topical retinoids (tretinoin, adapalene, tazarotene). Topical retinoids are vitamin A derivatives, and are crucial for acne treatment as they can unplug existing comedones, prevent new ones, reduce inflammation, and improve other topical agent penetration. Adapalene is the first topical retinoid approved for over-the-counter use for those 12 years and older.
  • Keratolytic agents: Help shed the outermost skin cells and include Benzoyl peroxide, Azelaic acid, and Salicylic Acid.
• Oral: Oral antibiotics (doxycycline, minocycline, tetracycline, erythromycin) are used for moderate to severe acne, suppressing P. acnes growth and inflammation. Oral retinoids (isotretinoin) are the principal agent for severe cases.
• Hormonal agents: Combination oral contraceptives (OCs) and spironolactone are used to reduce androgen activity, leading to decreased sebum production.

Patient Education for Acne Medications

• General precautions: Avoid sunlight, sunlamps, and tanning beds. Don't use harsh soaps or scrubs. Wash and dry skin before application and wash hands after use. Keep medications away from the eyes, mouth, and mucous membranes. Report severe irritation.
• Specific considerations: Avoid using benzoyl peroxide with dapsone. Women of childbearing age must strictly adhere to birth control using two reliable methods for isotretinoin.

Isotretinoin (Oral Retinoid)

• Black Box Warning: Associated with a high risk of birth defects and spontaneous abortion in developing fetuses, and should have strict, rigorous risk management in all transactions to ensure a woman is not pregnant, or becomes pregnant, while taking the medication. Patient education is essential.
• Monitoring: Perform blood tests and other assessments as needed.
• High-risk patients: Women capable of pregnancy who aren't adherent to birth control, younger patients who haven't reached full height, those with pre-existing diabetes mellitus or hyperlipidemia, or a history of depression or other mental illness.
• Adverse effects: Potential visual changes (especially night vision), sun sensitivity, psychological effects.

Key Prescribing Considerations & Treatment Goals

• Goal: To control acne, reduce nodular lesions, and prevent scarring.
• Baseline Data: CBC, glucose, lipid panel, liver function tests.
• Monitoring: Lipid and liver function tests every two weeks, then less frequently as needed. Verify birth control adherence for women of childbearing age. Assess for vision, mood, and pain changes.
• High-risk patient identification: Individuals mentioned above with critical factors
• Evaluating therapeutic effects: Look for reduction in nodular lesions and improvements to skin condition.
• Minimizing adverse effects: Advise avoidance of prolonged sunlight exposure.

Hormonal Agents

• Combination Oral Contraceptives (OCs): Effective for managing acne in women aged 15+, who need contraception. Their mechanism of action is related primarily to estrogen which suppresses ovarian androgen production and increases sex hormone-binding globulin, thus reducing androgen availability and thereby sebum production. Improvement can take 6+ months.
• Spironolactone: An androgen antagonist that blocks steroid receptors, including those for aldosterone and sex hormones. Used in combination with oral contraceptives if needed, and added after oral contraceptives are not adequate. It can cause menstrual irregularities, breast tenderness, and hyperkalemia.

Patient-Centered Care Across the Lifespan

• Children: Retinoids not recommended for <12 years, with exceptions. Other topical medications are suitable for >12 years but hormone therapy is not recommended prepubertally.
• Pregnant Women: Benzoyl peroxide and topical salicylic acid are the preferred OTC treatments. Retinoids are teratogenic. Avoid systemic sulfonamides as they are associated with complications in neonates.
• Breastfeeding Women: Caution is advised, particularly with systemic topical medicines such as oral or topical dapsone, due to unknown amounts excreted in breast milk.
• Older Adults: Safety and efficacy not established for all medications.