Effect of Environment on Skin

Question 1

What are Insults on the skin?

Consequences of skin damage?

What is Toxic Epidermal Necrolysis?

Answer 1

• Stresses that affect the skin e.g. Burns, Radiation, Microbes etc.
• Dehydration, Shock, Infection, Hypothermia, Impaired thermoregulation etc.
• Rare adverse drug reaction where epidermis peels off; can be fatal as dermis becomes exposed

Question 2

What are the 3 adaptations of the skin? Describe them

How does Tanning affect cells?

Answer 2

• 1. Sweating and Vasodilation in heat and Vasoconstriction in cold - FAST
     
     2. Hyperkeratosis (Callus formation); Thickening of Cornified layer on rubbing and pressure (e.g. guitar, weightlifting), or after UV exposure - SLOW
     3. Tanning; Melanocyte response after UV exposure - SLOW
• • Melanin protects against UV and DNA damage and therefore skin cancer
  • UV damages DNA in the basal keratinocyte to stimulate MSH (Melanocyte-stimulating hormone) production, which binds to MC1R on the melanocyte, creating cAMP = ↑Melanin synthesis and ↑Mitosis

Question 3

How does thermoregulation occur in the skin?

What happens if blood flow to the SVP is decreased for too long?

Answer 3

• There are AV shunts between arterioles and venules

When cold, shunts open to ↓blood flow and the opposite happens when hot to ↑blood flow to the Superficial Vascular Plexus/SVP just below the epidermis

• Frostbite (in severe colds)

Question 4

Abnormal effects of environment on skin:
What is Lichenification?

What is Sunburn?

What are Naevi/Moles? When can it be a risk, and what for?

What is Solar Elastosis?

What is Solar Keratosis?

Answer 4

• HYPERKARTOSIS; reaction to excessive rubbing or scratching from skin conditions
• Radiation burn causing inflammation and blistering from epidermal cell death due to severe DNA damage
• Benign proliferation of melanocytes; Many/Large naevi is a risk factor for Melanoma skin cancer
• Wrinkling due to loss of elasticity
• Dysplastic (abnormal) growth of keratinocytes

Question 5

What’s the most dangerous type of skin cancer?

What are the other less dangerous types of skin cancer?
→ How are they treated?

Answer 5

• MELANOMA; Most dangerous - Thin, Rapid spread
• Squamous cell carcinoma and Basal cell carcinoma
  → Surgery

Question 6

What are the 2 thickness types of burns?

What is lost with full thickness burns?

What are the symptoms of Dermatitis?

What are the 2 types of Dermatitis?

Answer 6

• • Partial Thickness - Superficial burn or up to Sebaceous glands
  • Full thickness - Deep burn up to Hypodermis, with Scar formation
• Pinprick sensation
• Redness, Itching, Swelling, Blistering
• • Irritant Contact dermatitis; occurs on too much exposure to a substance

• Allergic Contact dermatitis - allergy to something in contact with skin and a small amount can be enough to trigger immune system

Question 7

Give examples of Microbial Infections that can occur in the Integument. What type of microbe is it?

Answer 7

• Paronychia - nail fold infection - fungal/bacterial
• Tinea Capitis (Scalp Ringworm) - fungal
• Impetigo - bacterial
• Cellulitis - bacterial infection of subcutaneous tissue
• HPV/Warts - viral