Dermatology

### **Dermatology – Study of Skin Diseases** **Dermatology** is a clinical subject in **final-year MBBS**, covering **skin infections, autoimmune skin diseases, allergies, tumors, and cosmetic dermatology**. However, the basics of skin histology and pathology are covered in **second-year MBBS (Pathology & Microbiology).** --- ## **1. Basic Skin Anatomy & Physiology** - **Layers of Skin**: - **Epidermis** – Outer layer (Keratinocytes, Melanocytes, Langerhans cells) - **Dermis** – Middle layer (Collagen, Blood vessels, Nerve endings) - **Hypodermis** – Fat layer (Shock absorption, Insulation) - **Skin Functions**: Protection, Temperature regulation, Sensation, Vitamin D synthesis --- ## **2. Common Skin Infections** ### **Bacterial Skin Infections** - **Impetigo (Superficial Skin Infection)** - **Cause**: **Staphylococcus aureus, Streptococcus pyogenes** - **Symptoms**: **Honey-colored crusts** around mouth/nose - **Treatment**: **Topical Mupirocin, Oral Antibiotics (Cephalexin)** - **Cellulitis (Deep Skin Infection)** - **Cause**: **Streptococcus pyogenes, Staphylococcus aureus** - **Symptoms**: **Red, Warm, Swollen, Painful skin** - **Treatment**: Oral/IV **Antibiotics (Amoxicillin-clavulanate, Clindamycin)** - **Erysipelas (Superficial Dermal Infection)** - **Cause**: **Group A Streptococcus (GAS)** - **Symptoms**: **Well-demarcated, Bright red, Swollen rash** (Common on face & legs) - **Treatment**: **Penicillin, Cephalosporins** --- ### **Viral Skin Infections** - **Herpes Simplex Virus (HSV)** - **HSV-1 (Oral)** → Cold sores - **HSV-2 (Genital)** → Painful ulcers - **Treatment**: **Acyclovir, Valacyclovir** - **Herpes Zoster (Shingles - Reactivation of Varicella-Zoster Virus)** - **Symptoms**: **Painful, Vesicular rash along a dermatome** - **Treatment**: **Acyclovir, Painkillers, Gabapentin for nerve pain** - **Molluscum Contagiosum (Poxvirus Infection)** - **Symptoms**: Small, **Umbilicated papules** - **Treatment**: Cryotherapy, Curettage --- ### **Fungal Skin Infections (Tinea / Ringworm)** - **Tinea Capitis (Scalp) → Scaly patches, Hair loss** - **Tinea Corporis (Body) → Ring-shaped, Itchy rash** - **Tinea Pedis (Athlete’s Foot) → Cracks, Itching between toes** - **Tinea Unguium (Nails) → Thickened, Discolored nails** - **Diagnosis**: **KOH Mount, Wood’s Lamp Examination** - **Treatment**: **Topical Clotrimazole, Oral Terbinafine (Severe cases)** --- ### **Parasitic Skin Infections** - **Scabies (Sarcoptes Scabiei Mite Infestation)** - **Symptoms**: **Severe night itching, Burrows in finger webs** - **Treatment**: **Topical Permethrin, Oral Ivermectin** - **Pediculosis (Lice Infestation)** - **Head Lice, Pubic Lice** → Itchy scalp/pubic area - **Treatment**: **Permethrin Shampoo, Comb removal** --- ## **3. Inflammatory Skin Disorders** ### **Eczema (Atopic Dermatitis)** - **Symptoms**: **Itchy, Dry, Red skin, Flexural involvement (Elbows, Knees)** - **Treatment**: **Moisturizers, Topical Steroids, Antihistamines** ### **Psoriasis** - **Symptoms**: - **Well-demarcated, Scaly plaques on Elbows, Knees, Scalp** - **Nail pitting** - **Auspitz Sign** – Bleeding spots on removing scales - **Treatment**: - **Topical**: Steroids, Calcipotriol (Vit D analog) - **Systemic**: Methotrexate, Biologics (Adalimumab) ### **Lichen Planus ("4 Ps")** - **Symptoms**: **Purple, Polygonal, Pruritic, Papules** - **Common Sites**: Wrists, Oral Mucosa (White Striae - Wickham’s Striae) - **Treatment**: **Topical Steroids, Antihistamines** --- ## **4. Autoimmune Skin Diseases** ### **Bullous Pemphigoid (Tense Blisters in Elderly)** - **Symptoms**: **Large, Firm blisters** on skin (No oral involvement) - **Diagnosis**: **DIF (Direct Immunofluorescence) - IgG at Basement Membrane** - **Treatment**: **Steroids, Immunosuppressants** ### **Pemphigus Vulgaris (Fragile Blisters, Oral Involvement)** - **Symptoms**: **Painful Oral Ulcers, Skin Blisters that Rupture Easily** - **Diagnosis**: - **Positive Nikolsky Sign** – Blister spreads on rubbing - **DIF - IgG deposits on Epidermis ("Fishnet pattern")** - **Treatment**: **High-dose Steroids, Rituximab** --- ## **5. Skin Cancers** - **Basal Cell Carcinoma (Most Common, Least Aggressive)** - **Pearly Nodules, Rolled Borders, Telangiectasia** - **Treatment**: Surgical Excision - **Squamous Cell Carcinoma (SCC)** - **Red, Ulcerated Lesion with Scaling** - **Associated with Chronic Sun Exposure** - **Treatment**: Surgery, Radiation - **Melanoma (Most Aggressive, Can Metastasize)** - **"ABCDE Rule"** – Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolution - **Diagnosis**: Biopsy - **Treatment**: Surgery, Immunotherapy (Nivolumab) --- ## **6. Cosmetic Dermatology & Skin Procedures** - **Acne Vulgaris** → **Retinoids, Benzoyl Peroxide, Isotretinoin (Severe cases)** - **Vitiligo (Depigmentation)** → **Phototherapy, Steroids** - **Alopecia Areata (Hair Loss)** → **Steroids, Minoxidil** - **Botox & Fillers** → Anti-aging treatments --- ## **7. Study Tips for Dermatology** ✅ **Use mnemonics** (e.g., **"SOAP B" for Psoriasis Features - Scales, Onycholysis, Arthritis, Pitting, Bleeding**) ✅ **Learn to differentiate between bacterial, viral, and fungal skin infections** ✅ **Practice Nikolsky Sign, Auspitz Sign, and Wood’s Lamp Examination** ✅ **Refer to Rook’s or Fitzpatrick’s Dermatology textbooks** ---

Comments

Post a Comment

Popular posts from this blog

Brachial Plexus

 ### **Brachial Plexus Made Easy!** The **Brachial Plexus** is a **network of nerves (C5-T1)** that supplies the **upper limb**. It is crucial for movements and sensations of the arm. --- ## **1. Structure of the Brachial Plexus (Mnemonic: Randy Travis Drinks Cold Beer)** | **Part** | **Mnemonic** | **Components** | |----------|------------|--------------| | **Roots** | **R**andy | C5, C6, C7, C8, T1 | | **Trunks** | **T**ravis | Upper (C5-C6), Middle (C7), Lower (C8-T1) | | **Divisions** | **D**rinks | Each trunk has an **Anterior & Posterior Division** | | **Cords** | **C**old | Lateral, Medial, Posterior (named based on axillary artery) | | **Branches** | **B**eer | 5 Major Terminal Branches | --- ## **2. Major Branches & Their Functions** ### **1️⃣ Musculocutaneous Nerve (C5-C7)** ✔ **Motor:** Biceps Brachii, Brachialis, Coracobrachialis (**flexion of elbow**) ✔ **Sensory:** Lateral forearm ✔ **Injury:** Weak elbow flexion (e.g., stabbing injury) ### **2️⃣ Axillary Nerv...
Read more

Biochemistry

**Biochemistry** is one of the foundational subjects in **first-year MBBS**, focusing on the chemical processes in the human body. It helps in understanding **metabolism, enzymatic reactions, and molecular biology**. ### **Main Lessons in Biochemistry** #### **1. Biomolecules** - Carbohydrates (glucose, fructose, glycogen) - Proteins (amino acids, peptides, structural proteins) - Lipids (fatty acids, triglycerides, phospholipids) - Nucleic acids (DNA, RNA, nucleotides) #### **2. Enzymes & Metabolism** - Enzyme structure, function, and regulation - Enzyme kinetics (Michaelis-Menten equation) - Coenzymes and cofactors - Metabolism of carbohydrates, proteins, and fats - Glycolysis, Krebs cycle, and oxidative phosphorylation - Electron transport chain and ATP production #### **3. Vitamins & Minerals** - Water-soluble vitamins (B-complex, C) - Fat-soluble vitamins (A, D, E, K) - Role of minerals (iron, calcium, zinc, magnesium) #### **4. Molecular Biology & Genetics** - DNA repl...
Read more

Xrays

 No one knows the long-term effects of ultrasound use. Many practitioners feel that the technology is perfectly safe since studies of babies and their mothers have not determined any effects. Other practitioners are not so convinced of ultrasound safety and feel that judicious use is advised. Keep in mind that x-rays were in use for fifty years before the general public became aware of their negative effects. DES and thalidomide were initially thought to be safe, but it was later discovered that they were the root of cancer, sterility, and anomalies. The greatest risk of using ultrasound technology too much is that if an ultrasound raises a question about the health of the fetus, invasive and high-risk procedures and technologies may be used, which do carry obvious risks for the mother or her child. STUDIES Non-diagnostic ultrasound has demonstrated b8iological effects such as cell heating or thermal effects and cavitational activities using plants and animals. It is difficult to c...
Read more