Session 5.4b - Lecture 2 - Dermatology Flashcards
Slides 14 -
Fig. 14 (left)
Describe this rash.
A well-defined erythematous and scaly rash with a white silvery scale
Fig. 14 (left)
Give a differential diagnosis for this rash based on its appearance.
Psoriasis
What are typical places on the skin for psoriasis to present with?
- Skull
- Backs of ears
Fig. 14 (middle)
Give a differential diagnosis for this patient and explain why.
Erythematous and scaly rash that presents at the back of the ears - this is typical of psoriasis.
Other than the skin, where else can psoriasis affect?
- Joints (psoriatic arthritis)
- Nails
What are the typical changes in nail psoriasis?
- Little pits in the nail: pitting
- The nail plate can separate from the nail bed so it looks whiter: onycholysis
- Yellow or brown areas that look like a drop of oil under the nail: discolouration
- Nails can get really thickened: hyperkeratosis
What is onycholysis?
When the nail plate separates from the nail bed (appears whiter).
This is typical in psoriasis.
Fig. 14 (right)
What is this image showing?
Onycholysis (nail plate separation from the nail bed)
Fig. 14 (right)
Give a clinical condition this sign is typical of.
Sign - onycholysis
Condition - psoriasis
What does discolouration of the nails present as?
Yellow or brown areas that look like a drop of oil under the nail.
What is nail pitting?
Where little pits or dents present in the nail
What is it called when little pits present in the nail bed?
Nail pitting
What is it called when the nail plate separates from the nail bed?
Onycholysis
What is it called when yellow or brown areas appear under the nail?
Nail discolouration
What is hyperkeratosis?
When the nail (skin) gets really thickened
What is it called when you observe the nail being abnormally thicker?
Hyperkeratosis
Draw an image of how plaque psoriasis presents on a patient’s lower back.
See Fig. 14 (left)
Draw an image of how psoriasis presents in a typical location it is found.
See Fig. 14 (middle)
Backs of ears/scalp
Draw an image of someone’s nail who has nail psoriasis.
See Fig. 15 (right)
Show any of:
- pitting
- onycholysis
- discolouration
- hyperkeratosis
What is nail pitting a sign of?
It is very typical of psoriasis
What is onycholysis a sign of?
- Infection (fungal nail infections)
- Drugs
- Trauma
- Psoriasis/psoriatic arthritis
- Hyperthyroidism
What can discolouration of the nails be a sign of?
- Infection
- Psoriasis
What can hyperkeratosis of the nails be a sign of?
- Psoriasis
Fig. 15 (left)
Describe the lesions in this image.
Fluid-filled blisters (vesicles)
Fig. 15 (left)
Give a differential diagnosis for this image and explain why.
Cold sore - typical fluid-filled blisters (vesicles) on mouth.
How do cold sores typically present?
Fluid-filled blisters (vesicles)
Draw an image of a patient presenting with a cold sore.
See Fig. 15 (left)
Fluid-filled blisters (vesicles)
What are fluid-filled blisters (vesicles) on the mouth typical of?
Cold sores (caused by HSV).
Fig. 15 (right)
Describe the lesions seen in this image (2 marks).
Larger fluid filled blisters (1) which are called bulla (1).
2 marks for statement of bulla alone
Fig. 15 (right)
What is this condition?
Bullous pemphigoid - fluid-filled bulla quite commonly seen in the elderly.
What is bullous pemphigoid?
An autoimmune condition that causes itchy, red skin that presents with bulla. It commonly affects the elderly (> 60 y/o).
What age category does bullous pemphigoid primarily affect?
> 60 y/o (elderly)
Explain the pathophysiology of bullous pemphigoid.
It is an autoimmune disease, so the patients’ own body produces antibodies against their own skin - creating bulla as a result.
It is NOT contagious, an allergic reaction or affected by diet/lifestyle.
Draw an image showing how bullous pemphigoid typically presents.
See Fig. 15 (right)
Bulla in the elderly from autoimmune disease.
Fig. 16
Describe the lesion seen here.
Patient has developed redness (nodules) - this is inflammation deep on subcutaneous fat.
Fig. 16
Describe what would be felt on palpation?
Patient has developed redness, which is quite firm, and on palpation would feel quite deep (nodules) - this is inflammation deep on subcutaneous fat.
Fig. 16
What is the diagnosis?
Erythema nodosum
What is erythema nodosum?
Erythema nodosum is swollen fat under the skin causing red bumps and patches.
Erythema nodosum is a type of what group of diseases?
Panniculitis
What is panniculitis?
A broad term relating to inflammation of subcutaneous fat
What is the term used to described inflammation of subcutaneous fat?
Panniculitis
What causes erythema nodosum?
Erythema nodosum can be caused by lots of things but often the cause is not known. It is a reactive rash, and can be caused by infection, medication, sometimes even contraception, pregnancy.
Common causes include:
- Crohn’s disease
- ulcerative colitis
- a bad reaction to some medicines
- sarcoidosis
- tuberculosis
- pneumonia
- streptococcal infection
List 7 causes of erythema nodosum.
Accept any from:
- Crohn’s disease
- ulcerative colitis
- a bad reaction to some medicines
- sarcoidosis
- tuberculosis
- pneumonia
- streptococcal infection (NHS)
- infection
- medication
- contraception
- pregnancy (lecture)
How does erythema nodosum feel on palpation?
Firm and quite deep.
A patient presents with firm red nodules that are felt quite deep to the subcutaneous fat. They tell you they also have ulcerative colitis.
State a likely diagnosis.
Erythema nodosum
Draw how erythema nodosum would present on someone’s legs.
See Fig. 16
Red nodules from inflammation of the subcutaneous fat.
Fig. 17
Describe this mole.
- Multicoloured mole (developed different colours)
- has a nodular component
Fig. 17
Give a likely diagnosis and explain why.
Suspicious of a cancerous mole - skin cancer - melanoma - due to the appearance of >2 colours in the mole.
When should you be suspicious of a mole being cancerous?
Always be suspicious if it has >2 colours.
A patient presents with a mole that is light brown, dark brown, black, blue and grey. What can this be indicative of?
The mole has more than 2 colours, so you must be suspicious of cancer.
What does it mean if we say the mole is nodular?
That the mole is quite deep, thus the patient has a poor prognosis.
At what age group does melanoma affect?
Melanoma can occur in young people - more than a quarter of skin cancer cases are diagnosed in people under 50, which is unusually early compared to most other types of cancer.
Draw the appearance of a cancerous skin mole (melanoma).
See Fig. 17
(Multicoloured, nodular component).
Fig. 18
Describe what you can see.
Hair loss (alopecia) that has no signs of inflammation (scaliness, itchy, weepy).
Fig. 18
Give a likely diagnosis for this patient and explain why.
Alopecia areata - hair loss that has no inflammatory component, thus not a suspected fungal infection.
Fig. 18
Explain why this is unlikely to be a fungal infection.
Although their is hair loss (alopecia), there are no signs of inflammation, such as scaling, weeping or itching (excoriations - scratch marks) - thus, it is unlikely to be a fungal infection.
What is alopecia areata?
Alopecia areata is an autoimmune condition, that causes non-scarring hair loss which can occur at any age.
A patient presents with patches of hair loss with no visible signs of inflammation. Give a likely diagnosis.
Alopecia areata
What is the pathophysiology behind alopecia areata?
It is an autoimmune condition, so their own body is trying to attack hair follicle
Why do the hairs come back again in the future for alopecia areata?
Although it is an autoimmune condition where the body attacks the hair follicles, it is not a complete destruction of them, so the hairs come back again in the future.
How can you differentiate between a fungal infection of the scalp and alopecia areata?
A fungal infection would be scaly, itchy and weepy, whereas alopecia areata
Draw how the patient’s scalp would look in alopecia areata.
See Fig. 18
Typically, it starts as one or more bald, smooth patches on the scalp, which are not inflamed or scaly. It usually causes small, coin-sized, round patches of baldness on the scalp.
It tends to affect the pigmented hair so there may be some white hairs left within the bald area in older people.
Fig. 19
Label the layers of the skin.
- Epidermis
- Basement membrane
- Dermis
- Subcutaneous tissue
Fig. 19
Label the layers of the skin. Caption the image
- Epidermis
- Basement membrane
- Dermis
- Subcutaneous tissue
Structure of the skin
Draw a cross section of the skin and label the layers.
See Fig. 19
- Epidermis
- Basement membrane
- Dermis
- Subcutaneous tissue
Structure of the skin
Fig. 20 (left)
This image shows normal skin histology. Label the layers and include a key.
- stratum corneum
- quiescent epidermis
- blood vessels
Fig. 20 (right)
Describe this image.
Normal, elastic-looking skin.
Draw an image depicting the histology of normal skin.
See Fig. 20 (left)
- stratum corneum
- quiescent epidermis
- blood vessels
Draw an image depicting what healthy skin looks like.
See Fig. 20 (right)
Normal, elastic-looking skin. No plaques. Single colour. Blood vessels may or may not be visible.
Fig. 20 (left)
What is this figure showing?
Epidermis, the outer layer of the skin
Fig. 20 (left)
Which cells are alive in the epidermis?
The quiescent epidermis
Fig. 20 (left)
Which cells are dead in the epidermis?
Stratum corneum
Which layer of cells are dead in the epidermis?
Stratum corneum
Fig. 20 (left)
What are the red dots interlaced between the quiescent epidermis?
Tiny little blood vessels
Fig. 21 (top left)
Label the skin histology.
- stratum corneum
- quiescent epidermis
- blood vessels
Fig. 21 (bottom left)
Describe this image.
Normal, healthy skin.
Fig. 21 (right)
Give a diagnosis for this image.
Plaque psoriasis
Draw a picture of normal skin histology.
See Fig. 21 (top left)
- stratum corneum
- quiescent epidermis
- blood vessels
normal
Draw a picture of normal skin.
See Fig. 21 (bottom left)
Draw a picture of plaque psoriasis.
See Fig. 21 (right)
psoriasis
What happens to the epidermis in normal skin?
In normal skin, the epidermis has regenerated to normal pace, and the outermost layer of the epidermis, the stratum corneum, constantly shreds cells at a rate in keeping with the production of new skin cells, and that gives a healthy appearance.
What is constantly shedding in normal skin?
The stratum corneum - outermost layer of epidermis.
Why do plaques grow in psoriasis?
In psoriasis, there is an increased turnover in the quiescent epidermis (from the basal layer upwards to the granular layer - these are making more skin cells), so the skin is growing faster and accumulates in the stratum corneum. That leads to hyperproliferation and thickening of the epidermis - there’s not enough time for all those cells to shred, so it gets really thickened, so there’s lots of scaling and cracking on the surface (plaques), and the blood vessels are enlarged/increased