Integumentary - Viral Infections Midterm Notes PDF

**INTEGUMENTARY -- *Viral Skin Infections*** **1. Varicella-Zoster Virus (Chickenpox & Shingles)** - **Cause**: - Caused by the **Varicella-Zoster Virus (VZV)**, which is part of the **Herpesvirus family**. - **Pathophysiology**: - **Chickenpox**: The virus enters throug...

**INTEGUMENTARY -- *Viral Skin Infections*** **1. Varicella-Zoster Virus (Chickenpox & Shingles)** - **Cause**: - Caused by the **Varicella-Zoster Virus (VZV)**, which is part of the **Herpesvirus family**. - **Pathophysiology**: - **Chickenpox**: The virus enters through the **respiratory tract** and spreads to the bloodstream, leading to a **generalized vesicular rash**. - **Shingles**: After primary infection (chickenpox), the virus remains dormant in **nerve ganglia**. Reactivation (typically in older adults or immunocompromised individuals) leads to a **painful vesicular rash** along a **dermatomal distribution** (area of skin supplied by one spinal nerve). - **Transmission**: - **Highly contagious**, spreads via **airborne droplets** or **direct contact** with vesicle fluid from lesions. - **Risk Factors**: - **For chickenpox**: Contact with infected individuals, lack of vaccination, and being a child or an unvaccinated adult. - **For shingles**: Older age, **immunosuppression**, stress, or a history of **chickenpox infection**. **2. Herpes Simplex Virus (HSV)** - **Cause**: - Caused by **Herpes Simplex Virus type 1 (HSV-1)** (causes oral herpes) and **Herpes Simplex Virus type 2 (HSV-2)** (causes genital herpes). - **Pathophysiology**: - After the initial infection, the virus enters the **sensory neurons** and becomes dormant in the **dorsal root ganglion**. - **Reactivation** occurs due to **stress, trauma, or immunosuppression**, leading to the virus traveling back to the skin where it causes **painful vesicular eruptions** (cold sores or genital herpes). - **Transmission**: - Transmitted via **direct contact with lesions, saliva, or genital secretions**. - **HSV-1** is often transmitted via kissing or sharing items like lip balm, while **HSV-2** is transmitted through **sexual contact**. - **Risk Factors**: - **Direct contact** with infected individuals, weakened immune system, sharing personal items (like towels, lip balms), or exposure to unprotected **sexual contact**. **3. Human Papillomavirus (HPV)** - **Cause**: - Caused by the **Human Papillomavirus (HPV)**. Different strains cause different diseases, such as **common warts, plantar warts, and genital warts**. - **Pathophysiology**: - HPV infects **keratinocytes** of the skin and mucosa. - The virus promotes the **proliferation of keratinocytes**, leading to **thickened growths** (warts) on the skin or mucosa. - It remains latent and can reactivate, causing **recurrent warts**. - **Transmission**: - **Direct contact with infected skin or mucosa** (e.g., touching warts) or exposure to **contaminated surfaces** (like swimming pools or showers). - **Risk Factors**: - Contact with infected surfaces, immunosuppression, **sexual contact** (for genital warts), and use of communal showers/swimming areas. **Summary Table** **Condition** **Cause** **Pathophysiology** **Transmission** **Risk Factors** -------------------------------- ----------------------------------------- ------------------------------------------------------------------- ----------------------------------------------------------- ------------------------------------------------------ **Varicella-Zoster** **Varicella-Zoster Virus** Dormant in **nerve ganglia**, reactivates as shingles **Airborne droplets** or **direct contact** Age, prior infection, stress, **immunosuppression** **Herpes Simplex** **Herpes Simplex Virus (HSV-1, HSV-2)** Dormant in **nerve ganglia**, reactivates with triggers **Direct contact with lesions/saliva/genital secretions** Direct contact, stress, weakened immune system **Human Papillomavirus (HPV)** **HPV virus** Infects **keratinocytes**, promotes **excess keratin production** **Direct contact** with skin, mucosa, or objects Direct contact, communal surfaces, immunosuppression