Pharmacology of Acne — फ़ुल Hindi + English (MBBS/MD Level)
Author: mahfoozmedicalhealth | Category: Dermatology / Pharmacology | Updated: 17 August 2025
Contents (सूची)
- Introduction — क्या है Acne?
- Epidemiology & Impact
- Pathophysiology — मूल कारण
- Clinical Types & Assessment
- Topical Pharmacotherapy
- Systemic Pharmacotherapy
- Isotretinoin — Detailed
- Hormonal Therapy (Females)
- Special Populations & Pregnancy
- Antibiotic Resistance & Stewardship
- Treatment Algorithm
- Patient Counselling & Monitoring
- Internal Resources (Stay on site)
- Summary & Exam Tips
Introduction — क्या है Acne?
Acne vulgaris एक chronic inflammatory condition है जो मुख्यतः pilosebaceous unit (sebaceous gland + hair follicle) को प्रभावित करती है। यह adolescents में सबसे common है पर adults—ख़ासकर महिलाओं—में भी persistent हो सकती है। Lesions range from comedones (blackheads/whiteheads) to papules, pustules, nodules और cysts जो scarring कर सकती हैं।
इस लेख में हम pharmacology पर focus करेंगे: कौन से drugs काम करते हैं, उनका mechanism, indications, side effects, contraindications और monitoring — exam और clinical practice दोनों के लिए उपयोगी। लेख हिंदी और English दोनों में mix करके रखा गया है ताकि clinicians और students दोनों के लिए पढ़ना आसान रहे।
Epidemiology & Impact
Acne का lifetime prevalence adolescents में ~80–90% है। Severe forms (nodulocystic) कम common हैं लेकिन morbidity ज़्यादा देते हैं — permanent scarring, social stigma, और psychological effects जैसे depression और anxiety। इसलिए early, effective therapy clinically important है।
Pathophysiology — चार मुख्य pillars
Acne के pathogenesis को समझना जरूरी है ताकि pharmacologic therapy rationale के साथ choose की जा सके। मुख्य चार pathogenic mechanisms:
- Increased sebum production — Androgens (DHT, testosterone) sebaceous glands को stimulate करते हैं जिससे sebum ↑ होता है।
- Follicular hyperkeratinization — Abnormal desquamation → microcomedo → open/closed comedones।
- Cutibacterium acnes colonization — पहले Propionibacterium acnes कहा जाता था; यह sebum को fatty acids में todta hai → inflammation badhata hai।
- Inflammation — Innate (TLR2 mediated) और adaptive immune responses IL-1, TNF-α, IL-8 आदि के माध्यम से lesion बनाते हैं।
Clinical types & Assessment — किसे क्या देना चाहिए
Lesion type और severity treatment को direct करते हैं:
- Comedonal acne: Open/closed comedones — topical retinoids best.
- Mild-moderate inflammatory acne: Papules/pustules — topical retinoid + benzoyl peroxide ± oral antibiotic for short course.
- Severe nodulocystic acne: Deep nodules, cysts — risk of scarring; often isotretinoin indicated.
Severity assessment tools: Leeds grading, Global Acne Grading System — पर clinic में अक्सर mild/moderate/severe simplification use होता है। Assess psychosocial impact, pregnancy potential, prior therapy और scarring risk।
Topical Pharmacotherapy — first-line for mild disease
Topical Retinoids (Tretinoin, Adapalene, Tazarotene)
Mechanism: Retinoids bind RARs → normalize keratinocyte desquamation, comedolytic effect, anti-inflammatory via TLR modulation।
Use: Comedonal और inflammatory acne दोनों में first-line। Adapalene धीरे-धीरे tolerated होता है; tazarotene सबसे potent पर ज़्यादा irritation और teratogenic risk (अधिक सावधानी)।
Side effects: Local irritation, peeling, photosensitivity — moisturizer और sunscreen recommend करें।
Benzoyl Peroxide (BPO)
Mechanism: Releases oxygen free radicals → bactericidal against C. acnes; keratolytic & comedolytic।
Use: Combine with topical antibiotics to reduce resistance; available 2.5% – 10% formulations।
Side effects: Irritation, dryness, bleaching of clothes/towels.
Topical Antibiotics (Clindamycin, Erythromycin)
Mechanism: 50S ribosomal inhibition → reduce bacterial load and inflammation।
Important: कभी भी topical antibiotic को monotherapy में न दें — हमेशा BPO या retinoid के साथ combine करें resistance रोकने के लिए।
Azelaic Acid, Dapsone, Sulfur
Azelaic acid — antimicrobial, keratolytic और post-inflammatory hyperpigmentation में मददगार। Topical dapsone (5% gel) inflammatory acne especially adult females में useful। Sulfur-based preparations sensitive skin वाले patients के लिए option।
Systemic Pharmacotherapy — moderate to severe
Oral Antibiotics
Common drugs: Doxycycline 100 mg once/twice daily, Minocycline 50–100 mg once daily, Azithromycin pulses in some protocols.
Mechanism: Antibacterial + anti-inflammatory (inhibit neutrophil chemotaxis, MMPs, cytokines)।
Duration: Shortest effective period — usually 6–12 weeks; re-evaluate and step-down to topical maintenance.
Side effects & cautions: Tetracyclines — photosensitivity (doxycycline), contra in pregnancy and children <8 yrs. Minocycline — dizziness, pigmentation, rare autoimmune hepatitis. Macrolides — GI upset, resistance concerns.
Oral Isotretinoin — overview
निम्न भाग में isotretinoin का विस्तार होगा (special section)।
Hormonal therapy (females)
Combined oral contraceptives (COCs): Estrogen + progestin reduce ovarian androgen production और increase SHBG → free testosterone घटता है। Useful when acne hormonal pattern दिखे जैसे menstrual flares, hirsutism आदि।
Spironolactone: 50–200 mg/day; anti-androgenic (androgen receptor blocker). Monitor potassium in susceptible patients; contraindicated in pregnancy।
Adjuncts
- Zinc: modest anti-inflammatory benefit (e.g., zinc sulfate 220 mg BD in some regimens)।
- Short-course oral steroids: For marked inflammatory nodules prior to definitive therapy (e.g., prednisone 0.5–1 mg/kg short course) — use carefully।
Isotretinoin — Detailed Guide (सबसे powerful drug)
Mechanism: Multi-target: reduces sebaceous gland size & sebum production, normalizes follicular epithelial differentiation (↓ microcomedones), decreases inflammation and indirectly reduces C. acnes by altering sebum environment।
Indications
- Severe nodulocystic acne
- Acne resistant to combined topical + oral antibiotic therapy
- Acne with high scarring risk or severe psychological impact
Dosing & cumulative strategy
Common approach: 0.5–1 mg/kg/day (divided) adjusted for tolerance; aim total cumulative dose 120–150 mg/kg over treatment course (commonly 4–6 months)। Some clinicians use lower-dose long-course regimens; individualized dosing required based on response and adverse effects।
Monitoring
- Baseline LFTs, fasting lipid profile
- Monthly pregnancy tests for women of childbearing potential (strict contraception counseling)
- Periodic LFTs & lipids (often at 1–2 months then as needed)
- Psychological assessment for mood changes
Adverse effects
- Mucocutaneous: cheilitis, xerosis, dry eyes, epistaxis
- Hyperlipidemia (↑ triglycerides)
- Raised transaminases
- Musculoskeletal: myalgia, transient ↑ CK in rare cases
- Teratogenicity — severe birth defects if used in pregnancy (absolute contraindication)
- Possible mood changes — monitor and counsel
Hormonal Therapy — women के लिए विशेष
When to suspect hormonal acne: adult onset, perimenstrual flare, persistence despite topical therapy, associated hirsutism or irregular menses।
Combined Oral Contraceptives (COCs)
COCs containing ethinyl estradiol + appropriate progestin reduce ovarian androgen production and increase SHBG → free testosterone ↓ → sebum production ↓। Choose preparations approved for acne where available। Contraindications: smoking (age>35), thromboembolism risk, uncontrolled hypertension।
Spironolactone
Mechanism: Aldosterone antagonist with anti-androgenic effect (inhibits androgen receptor and decreases androgen synthesis)। Dose 50–200 mg/day. Monitor potassium in patients with risk factors (renal disease, ACEi etc.). Use contraception — teratogenic potential not proven but avoid in pregnancy.
Special Populations & Pregnancy Considerations
Pregnancy
Avoid isotretinoin (absolute contra), topical retinoids (avoid), tetracyclines (contra). Safer options: topical azelaic acid, topical erythromycin, and cautious use of benzoyl peroxide (systemic absorption low). Always consult obstetrician/dermatologist for pregnant patients।
Adolescents
Avoid tetracyclines in children <8 years; focus on topical therapy and dermatology referral for severe cases।
Antibiotic Resistance & Stewardship
C. acnes resistance to macrolides and tetracyclines is an emerging problem। Stewardship principles:
- Avoid antibiotic monotherapy (topical or systemic)।
- Combine topical antibiotic with benzoyl peroxide or retinoid.
- Use oral antibiotics only for shortest effective duration (6–12 weeks) और long-term control के लिए non-antibiotic options पर switch करें (isotretinoin, hormonal therapy)।
- Monitor regional resistance patterns if possible and adjust practice accordingly।
Practical Treatment Algorithm — आसान तरीका
- Mild (comedonal): Topical retinoid nightly ± BPO morning।
- Mild-moderate inflammatory: Topical retinoid + BPO + topical clindamycin (short) OR oral doxycycline + topical retinoid + BPO।
- Moderate-severe / nodular: Oral antibiotic short-term + topical maintenance; consider isotretinoin early if scarring risk high।
- Severe/Scarring: Isotretinoin under specialist care।
- Female with hormonal signs: Consider COC or spironolactone (after excluding pregnancy)।
Individualize treatment: age, pregnancy plans, comorbidities, cost, patient preference और local guidelines को ध्यान में रखें।
Patient Counselling & Monitoring — practical tips
General counselling
- Treatment takes time — initial response 6–12 weeks। Patients को realistic expectation दें।
- Skin care: gentle cleanser, non-comedogenic moisturizer, sunscreen daily (retinoid users)।
- Avoid mechanical picking/squeezing — scarring risk बढ़ता है।
- Report severe side effects (unexplained mood changes, severe GI symptoms, jaundice, marked muscle pain)।
Isotretinoin specific counselling
- Two effective contraception methods required for women of childbearing potential; monthly pregnancy tests अपेक्षित।
- Avoid vitamin A supplements (hypervitaminosis A) and tetracyclines concurrently।
- Baseline LFTs & fasting lipids; monitor periodically।
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Summary & Exam Tips — मुख्य बातें
- Acne pathogenesis: ↑ sebum, follicular hyperkeratosis, C. acnes colonization, inflammation.
- Topical retinoids + benzoyl peroxide = backbone for mild-moderate acne.
- Oral antibiotics → use short-term and not as monotherapy due to resistance.
- Isotretinoin affects सभी pathogenic steps — reserved for severe/refractory cases; teratogenic है, इसलिए strict pregnancy prevention आवश्यक।
- Hormonal therapy (COCs, spironolactone) particularly helpful for women with endocrine features.
Exam prompt memory aid: "Four pillars (Sebum, Keratinization, C. acnes, Inflammation) — treat 1 or more with combination therapy; isotretinoin treats all four."