Lecture 22 - Dermatology

Question 1

What is Psoriasis?
What is it caused by?
What are the common triggers?

Answer 1

• Psoriasis is a skin condition leading to red, flaky patches of skin covered with silver scales on the extensor surfaces of the body. (elbows, knees, scalp)
• Caused by fast replacement of skin cells. Keratinocyte transport to corny layer takes 3-7 days instead of 28-40.
• Injury to skin, excessive drinking, smoking, stress, hormonal changes, immune disorders and certain medicines.

Question 2

What is Eczema?
When does it develop?
What is it triggered by?

Answer 2

• An atopic dermatitis that results in itchy, red, dry and cracked skin on flexor surfaces/creases of skin
• Often develops in connection with other conditions (asthma and hay-fever)
• 90% of people w/food allergies + eczema have symptoms triggered by milk, eggs, peanuts, wheat, soy, fish etc - but may also be triggered by soaps, detergents and stress.

Question 3

What is a malignant melanoma?
What are the common appearances/types of this?
What can cause production of these melanomas?

Answer 3

• A skin cancer that can metastasise to other organs, resulting in moles.
• Nodular melanoma, black/red in colour often found in the head, neck chest or back.
• Lentigo melanoma (10%), initially flat and develop sideways, look like a large freckle that gradually gets larger.
• Intense exposure to sunlight (UV rays), sun-bed exposure, particularly in people with freckles, fairer/pale skin and red/blonde hair.

Question 4

What is vitiligo?
What are the 2 main types?
Which type is most common?
What causes Vitiligo?

Answer 4

• A long-term condition where pale white patches develop on skin due to a lack of pigment (melanin). Most commonly on the head, neck and hands. Can also affect hair roots, turning hair white/grey leaving the areas susceptible to UV damage.
• Non-segmental (symptoms appear on both sides of the body symmetrically) and segmental vitiligo (patches only appear on one side of the body).
• Non-segmental (9 in 10). Segmental more common in children than adults (3 in 10).
• Non-segmental is an autoimmune condition where T-cells attack healthy melanocytes. Segmental is caused by neuro chemicals (e.g.: neuropeptide Y) released from nerve endings in skin cause cause an increase in ROS’s, which causes destruction of melanocytes.

Question 5

What is alopecia areata?

What is it caused by?

Answer 5

• Spot baldness, where hair is lost from some or all areas of the body.
• Thought to be a symptom of an autoimmune disorder in which body attacks its own hair follicles and stops hair growth

Question 6

Define:

Calor
Dolor
Rubor
Tumor
Pruritis

Answer 6

Calor = Heat 
Dolor = Pain
Rubor = Redness
Tumor = Swelling/Inflammation
Pruritis = Itching