Lecture 4 - skin conditions

Question 1

What are the three layers of the skin?

Answer 1

Epidermis (outer layer), Dermis (middle layer), Hypodermis (bottom subcutaneous layer)

Question 2

What are the 7 functions of the skin?

Answer 2

Protection, Sensation, Regulates temperature, Stops water loss, Makes vitamin D, Fights germs

Question 3

Describe the process of keratinocytes differentiation.

Answer 3

In the basal layer (stratum basale), keratinocytes are created and start making keratin. As they move up through the spinous layer (stratum spinosum), they form desmosomes. In the granular layer (stratum granulosum), they release lipids. In areas like palms and soles, they pass through the clear layer (stratum lucidum). Finally, in the cornified layer (stratum corneum), they become flat, dead cells filled with keratin.

Question 4

How long does it take for keratinocytes to mature and form the cornified layer?

Answer 4

28 days

Question 5

What happens if the keratinocyte differentiation process is disturbed?

Answer 5

Keratinocytes become leaky, dry, weak, and cannot produce the right proteins, leading to rough skin texture and increased susceptibility to infection and inflammation.

Question 6

What are some skin conditions that can develop from disturbed keratinocyte differentiation?

Answer 6

Psoriasis, Dermatitis

Question 7

Briefly describe the process of inflammation in the skin.

Answer 7

white blood cells release cytokine and chemokines to trigger more white blood cells so that they can end up attacking the keratinocytes of the skin causing them to proliferate

Question 8

What does inflammation of the skin normally cause?

Answer 8

Redness, Swelling, Pain, Increased itching

Question 9

Describe the innate response. (Psoriasis)

Answer 9

The white blood cells in the skin have special receptors called Pathogen Recognition Receptors that identify the kertainocyted as foreign and release cytokines to further recruit more immune cells to bring about inflammation.

Question 10

What does the adaptive immune system do when notified?

Answer 10

It generates specific T and B cells to fight the invader.

Question 11

What subsets of T cells are involved in the immune response?

Answer 11

TH1, TH2, TH11, TH17

Question 12

What do emollients do to the skin?

Answer 12

Provide a layer of oil that acts as a barrier, keeping moisture in.

Question 13

What is the role of occlusion in skin care?

Answer 13

Occlusion slows down water loss from the skin by providing a layer of oil.

Question 14

How do humectants benefit the skin?

Answer 14

Humectants increase the skin’s ability to hold water, helping retain moisture.

Question 15

What does lubrication do for the skin?

Answer 15

Lubrication allows the skin to glide more easily, reducing friction and irritation.

Question 16

How can we help the skin?

Answer 16

Provide emollients, directly tackle the cause, and combat aspects like inflammation and dryness.

Question 17

What is psoriasis?

Answer 17

Psoriasis is a chronic, relapsing-remitting papulo-squameous skin condition that can affect any part of the skin.

Question 18

What is the incidence of Psoriasis and is it different in males and females?

Answer 18

The incidence is 1-2% and is similar in both males and females.

Question 19

Which areas of the skin does psoriasis most commonly affect?

Answer 19

Knees, elbow, scalp, back

Question 20

What conditions can arise as a result of psoriasis or make it worse?

Answer 20

Hypertension, Obesity, Smoking, Alcohol, Mental health

Question 21

Describe the pathology of psoriasis.

Answer 21

Dendritic cells release IL-12 to stimulate CD4+ T cells, leading to inflammation and rapid proliferation of keratinocytes.

Question 22

What are common topical treatments for skin conditions?

Answer 22

Emollient, Cold tar, Dithranol, Corticosteroids, Tazarotene, Vitamin D analogues

Question 23

What is the function of emollients?

Answer 23

Occlusion, Humification, Lubrication

Question 24

What does cold tar do?

Answer 24

Reduces inflammation.

Question 25

What does dithranol do?

Answer 25

Inhibits proliferation of keratinocytes.

Question 26

What do corticosteroids do?

Answer 26

Reduce inflammation and treat flare-ups.

Question 27

What do Tazarotene and Vitamin D analogues do?

Answer 27

Help reduce proliferation, increase differentiation, and reduce inflammation.

Question 28

What are some more severe treatments used in psoriasis?

Answer 28

1. Narrowband UVB light 2. Systemic treatments Ciclosporin (IL 2 inhibitor in T cells) Methotrexate 3 . Biologics (injected into the skin) infliximab, adalimumab Etanercept Ustekinumab

Question 29

Explain how Narrowband UVB light helps treat psoriasis.

Answer 29

It shifts the TH1 mediated condition into a TH2 mediated condition, suppressing inflammation.

Question 30

How does cyclosporine treat psoriasis?

Answer 30

Stops T cells from proliferating and producing IL-2.

Question 31

How does methotrexate treat psoriasis?

Answer 31

Kills T cells and dendritic cells, inducing apoptosis.

Question 32

How do biologics help treat psoriasis?

Answer 32

They inhibit certain cytokines released from CD4+ T cells.

Question 33

What is dermatitis?

Answer 33

Patches of skin that are dry, itchy & flaky.

Question 34

What are the different types of dermatitis?

Answer 34

Atopic dermatitis, Contact (allergic/irritant) Dermatitis, Seborrheic dermatitis

Question 35

What triggers atopic dermatitis?

Answer 35

Genetic makeup, cold air, stress, inhalation of allergens.

Question 36

What triggers contact dermatitis (irritant)?

Answer 36

Direct damage from irritants like soaps, detergents, or chemicals.

Question 37

What triggers contact allergic dermatitis?

Answer 37

Something touching the skin, like jewelry or latex.

Question 38

What triggers Seborrheic Dermatitis?

Answer 38

Overgrowth of yeast on the epidermis.

Question 39

Briefly explain the pathogenesis of Atopic dermatitis (eczema).

Answer 39

CD4+ T cells differentiate into TH2 cells, which recruit B cells that release IgG antibodies.

Question 40

What TH cells might cause atopic dermatitis in Asian populations?

Answer 40

TH17

Question 41

Briefly explain the pathogenesis of allergic contact dermatitis.

Answer 41

Nickel is absorbed through the skin, stimulating TH1 cells which remember the allergen for future reactions.

Question 42

What is the name given to the reaction in allergic contact dermatitis?

Answer 42

Type IV delayed hypersensitivity.

Question 43

What are three things we must know about irritant contact dermatitis?

Answer 43

Caused by direct damage, can cause inflammation, and has periods of symptom relief.

Question 44

What are some treatments used for atopic dermatitis?

Answer 44

Topical steroids, Tacrolimus, Methotrexate, Ciclosporin, Tralokinumab

Question 45

What are some treatments used for contact allergic dermatitis?

Answer 45

Emollients, Topical steroids, UV therapy, Tacrolimus

Question 46

What are some treatments used for contact irritant dermatitis?

Answer 46

Remove irritant, Lotions, Topical steroids

Question 47

Why are antihistamines not used for dermatitis?

Answer 47

Not effective and cause sedation.

Question 48

Define impetigo.

Answer 48

Skin infection caused by bacteria - staphylococcus aureus & streptococcus pyogenes.

Question 49

Which population does impetigo occur in?

Answer 49

Children and people with poor hygiene.

Question 50

What does impetigo look like?

Answer 50

Honey crust on face & hands.

Question 51

What is recommended for impetigo treatment?

Answer 51

Remove crusts using saline solution or olive oil.

Question 52

What would you recommend if the impetigo is superficial?

Answer 52

Topical antibiotics - fusidic acid.

Question 53

What would you recommend if the impetigo was deeper?

Answer 53

Oral antibiotics - penicillin/flucloxacillin or erythromycin.

Question 54

When else might erythromycin be good to use?

Answer 54

For streptococcal nephritis.

Question 55

If a patient has a mild case of impetigo and you are reluctant to use antibiotics, what could be used instead?

Answer 55

1% hydrogen peroxide cream.

Question 56

What is the difference between chickenpox & shingles?

Answer 56

Chickenpox are small, red bumps all over the skin, while shingles is a painful rash usually on one side of the body.

Question 57

What virus causes chickenpox & shingles?

Answer 57

Varicella zoster virus.

Question 58

How does VZV infect the skin?

Answer 58

It enters the respiratory system and travels through the bloodstream to the skin.

Question 59

Briefly explain the pathogenesis of chickenpox/shingles.

Answer 59

VZV is inhaled, travels to skin cells, replicates, and can later reactivate in nerve cells.

Question 60

What is used to treat VZV?

Answer 60

Paracetamol, Calamine lotion, Piriton.

Question 61

What can be used to treat severe cases of chickenpox in adults or shingles?

Answer 61

Aciclovir, vaccinations.

Question 62

What are candida albicans?

Answer 62

A fungal infection that causes red, itchy rashes due to overgrowth of yeast.

Question 63

What enzyme does the candida albicans fungus use to penetrate the skin?

Answer 63

Hydrolytic enzymes like aspartic proteases and lipases.

Question 64

How do dendritic cells respond to fungal infection?

Answer 64

They engulf both the yeast and the hyphae of the fungus.

Question 65

What immune response does the yeast part of the fungus initiate?

Answer 65

A TH1 response.

Question 66

What immune response does the hyphae part of the fungus initiate?

Answer 66

A TH2 response.

Question 67

Which cells clear an initial fungal infection?

Answer 67

Neutrophils and macrophages.

Question 68

What is the treatment for candida albicans?

Answer 68

Clotrimazole 1% cream.

Question 69

How can you distinguish between a bacterial, fungal, viral skin condition?

Answer 69

By evaluating symptoms, appearance, and response to treatments.

Question 70

What is pediculosis corpus infestation?

Answer 70

An infestation of lice on the head, body, or pubic areas.

Question 71

Who is most commonly affected by pediculosis?

Answer 71

Children.

Question 72

What cells clear an initial fungal infection?

Answer 72

Neutrophils and macrophages (as part of the innate immune response).

Question 73

What is the treatment that can be used for candida albicans (fungal skin infections)?

Answer 73

Clotrimazole 1% cream.

Question 74

How can you distinguish between a bacterial, fungal, viral skin condition?

Answer 74

HEAD LICE.

Question 75

What is pediculosis corpus infestation?

Answer 75

An infestation of lice on the head (capitis) or body or even the pubic areas (pubis).

Question 76

Who is most commonly affected by pediculosis?

Answer 76

Children and vagrants (people that don’t have a permanent home).

Question 77

What are the clinical features of pediculosis infestation?

Answer 77

You might see itchy “dots” on the hair, louse eggs (nits) on the hair, and dermatitis from bites.

Question 78

What are the treatments for pediculosis?

Answer 78

Hedrin shampoo and Permethrin lotion (neurotoxin) to kill lice, used with a wide tooth knit comb.

Question 79

What are scabies?

Answer 79

This is a skin condition caused by tiny mites called Sarcoptes Scabiei.

Question 80

How does scabies spread?

Answer 80

From close skin-skin contact, often in crowded environments.

Question 81

How is scabies caused?

Answer 81

The female mite burrows into the top layer of skin (epidermis), lays their eggs, and has a 14-day cycle.

Question 82

What type of immune response is triggered by scabies?

Answer 82

An allergic TH2 cell response - IgG production - longer term T cell reaction.

Question 83

Explain briefly what a longer term T cell reaction looks like?

Answer 83

Longer-term T-cell response involves T-cells recognizing the scabies mites more specifically over time.

Question 84

What are the common features of scabies in infants and children?

Answer 84

Severe itching, often in the fingers, body folds, and feet, with lesions sometimes appearing in lines.

Question 85

What is the standard treatment for scabies?

Answer 85

Permethrin lotion (applied from head to toe for 24 hours) and oral ivermectin.

Question 86

What treatment is recommended for scabies in babies?

Answer 86

2.5% Sulphur ointment, which is very safe for babies.