Dermatology

Question 1

Describe important points to highlight when taking a dermatology history of the presenting complaint. (7)

Answer 1

Nature - rash vs lesion
Site
Duration
Initial appearance and evolution
Symptoms (esp itch and pain)
Aggravating or relieving factors
Previous and current treatment, effective or not.

Question 2

Describe the important past medical history of a patient presenting with a dermatological condition. (5)

Answer 2

Systemic disease
History of atopy (asthma, hay fever)
History of skin cancer or precancer. 
History of sunburn / sun bed use 
Skin type

Question 3

Describe important family history conditions to ask about in a patient presenting to dermatology. (3)

Answer 3

Skin disease
Atopy
Autoimmune disease

Question 4

Describe important social history things to ask about in a patient presenting to dermatology. (3)

Answer 4

Occupation - does it improve when away from work?
Sun exposure
Contact with irritants

Question 5

Describe important drug history things to ask about in a patient presenting to dermatology. (3)

Answer 5

Regular medications
Recent changes
Systemic and topical.

Question 6

Describe the stages of examination of the skin. (4)

Answer 6

Inspect
Palpate
Describe
Systematic check - all of skin, mucous membranes, hair, nails.

Question 7

Describe the stages of examining a rash. (4)

Answer 7

SCAM
Site - distribution
Colour and Configuration
Associated changes eg surface features
Morphology

Question 8

Describe the stages of examining lesions, and explain what the worrying feature would be in each category. (8)

Answer 8

ABCD
Asymmetry - asymmetrical is bad. 
Border - irregular or blurred
Colour - multiple is bad 
Diameter - over 6mm is worrying.

Question 9

Describe the 4 categories for site and distribution of a rash. (8)

Answer 9

Generalised - all over
Flexural - in the inside of joints eg backs of knees
Extensor - on the fronts of joints eg elbows
Photosensitive - only where the light touches eg declotage

Question 10

Describe the 4 categories for configuration of rashes. (8)

Answer 10

Discrete - separate blobs
Confluent - uniform, fading to nothing
Linear - in a line
Target - rings of different colours.

Question 11

Describe the 4 categories describing colour of rashes. (8)

Answer 11

Erythematous - red and blanching
Purpuric - red/purple and non-blanching
Pigmented - brown or black
Hypopigmented - loss of colour

Question 12

Describe the 4 categories of surface features of rashes. (8)

Answer 12

Scale - build up of keratin.
Crust - dried up exudate
Excoriation - erosion from scratching, indicates itchiness.
Erosion / ulceration - partial or full thickness loss of tissue.

Question 13

Describe 12 features of the morphology of rashes. (24)

Answer 13

Macule - flat blob
Papule - raised lump
Patch - big macule 
Plaque - big papule, often scaly
Nodule - big lump, often with blood vessels in. 
Vesicle - fluid filled, white 
Pustule - fluid filled, pus
Bulla - very large, fluid filled, like a blister. 
Annular - ring with a clearer centre. 
Wheal - smooth plaques
Discoid - like an annular, but erythematous and scaly centre. 
Comedone - tiny spots, common in acne.

Question 14

Describe three hair findings. (6)

Answer 14

Alopecia - can be patchy or diffuse
Hypertrichosis - hair where hair shouldn’t be eg on moles.
Hirsuitism - male pattern hair in women, esp in PCOS.

Question 15

Describe 4 nail findings. (8)

Answer 15

Koilonychia - spoon shaped nails indicating iron deficiency.
Pitting - dents in nails
Onycholysis - separating of nail from finger common in psoriasis
Clubbing - common in CVS or Resp disease.

Question 16

Describe 5 functions of the skin. (5)

Answer 16

Protective barrier against environmental insults. 
Temperature regulation
Sensation
Vitamin D synthesis 
Immunosurveillance.

Question 17

Describe erythroderma as a condition of the skin. (4)

Answer 17

Widespread redness of the skin commonly caused by psoriasis, eczema or drugs.
Symptoms: pruritus, fatigue, anorexia.
Signs: erythematous, scaly, thickened, inflamed.

Question 18

Describe the 4 cell types in the epidermis and their functions. (8)

Answer 18

Keratinocytes - protective barrier
Langerhan’s cells - APC
Melanocytes - produce melanin, a pigment that protects cell nuclei from UV DNA damage.
Merkel cells - specialised nerve endings for sensation.

Question 19

Name the 4 layers of the epidermis. Give both names. (8)

Answer 19

Horny - stratum corneum
Granular - stratum granulosum
Prickle cell - stratum spinosum
Basal - stratum basale 
Can (horny) guys suck (prickly) boobs?

Question 20

Describe the three changes to epithelial surface that can be a manifestation of pathology. (3)

Answer 20

Change in epidermal turnover
Change in skin surface
Change in pigmentation of the skin.

Question 21

Describe the dermis. (4)

Answer 21

Composed of elastin, collagen and glycosaminoglycans to provide strength and elasticity.
Also contains immune cells, nerves, lymphatics, and blood vessels.

Question 22

Describe sebaceous glands. (5)

Answer 22

Produce sebum through hair follicles and secrete it onto skin for lubrication.
Active only after puberty because stimulated by conversion of androgen to dihydrotestosterone.

Question 23

Describe the pathophysiology of acne vulagris. (2)

Answer 23

Increased sebum production leads to bacterial colonisation.

Question 24

Describe the differences and similarities between Eccrine and Apocrine glands. (6)

Answer 24

Sweat glands that regulate body temperature due to sympathetic innervation.
Eccrine glands are widespread.
Apocrine glands are active following puberty and are found in the axillae, areoles, genitalia and anus.

Question 25

Describe the structure of a nail. (4)

Answer 25

A nail plate that arises from time he nail matrix and rests on the nail bed, which is highly vascular.

Question 26

Describe atopic eczema:
Presentation (3)
History (2)
Complications (4)
Treatments (3)

Answer 26

Vesicles, bullae and papules.
Often has a personal or family history of atopy.
Complications include heavy bacterial colonisation, eczema herpeticum (herpes infection), contact allergies and reduced QoL.
Treatments include avoiding exacerbating factors, using emollients and using topical steroids.

Question 27

Describe urticaria.
Presentation (3)
Cause (1)
Treatments (3)

Answer 27

Erythematous, pruritus wheals.
Formed due to histamine release.
Treatments include eliminating underlying cause (eg drug reactions), taking high dose antihistamines or taking oral steroids.

Question 28

Describe molluscum contagiosum.
Presentation (4)
Treatment (2)

Answer 28

A pox virus that presents with papules (characteristically with a central dimple), common in atopy or immunocompromisation.
Most self-resolve in 6-9 months without treatment.

Question 29

Describe a tinea infection.
Type of infection (2)
Presentation and treatment factors (4)

Answer 29

Dermatophyte fungi infection causing a tinea (ringworm) infection.
Presentation depends on site and strain involved.
Treatment can be systemic or topical (depends).

Question 30

Describe a drug exanthem reaction. (3)

Answer 30

A cell mediated immune reaction causing a macular-papular rash. Treated by removing the offending drug.

Question 31

Describe Shingles.
Presentation (6)
Complications (4)
Treatment (1)

Answer 31

Presents dermatomally with burning pain. Attack results from reactivation of the latent virus hiding in the dorsal root ganglion since an earlier episode of varicella zoster infection (chicken pox). This means the elderly and immunocompromised are at risk.
Complications include secondary bacterial infection, paralysis, corneal ulcers and scaring (if Va involved).
Treated with systemic aciclovir.

Question 32

Describe simple squamous epithelium. (3)

Answer 32

Very thin, one cell thick layer.

Used for gas exchange.

Question 33

Describe simple cuboidal epithelium. (5)

Answer 33

Single layer of polygonal cells that have the same height and width.
Used for hormone synthesis, absorption and secretion.

Question 34

Describe simple columnar epithelium. (4)

Answer 34

Cells whose height is larger than their width. Sometimes have microvilli.
For absorption, secretion and lubrication.

Question 35

Describe pseudostratified epithelium. (5)

Answer 35

All cells touch the basement membrane, but not all reach the surface.
Lines the nasal cavity, trachea and bronchi.
Secretion and particle trapping.

Question 36

Describe stratified squamous epithelium. (3)

Answer 36

Top layer is squamous cells, like in the oral cavity. Protects against abrasion and reduces water loss.

Question 37

Describe stratified squamous keratinised epithelium. (5)

Answer 37

Outer layer has lost its nuclei and become keratinous. Found anywhere you can put a penis - vagina, anus, mouth, ear. Keratinocytes mitosis occurs in the basal layer (bottom of four).

Question 38

Describe transitional epithelium. (3)

Answer 38

Multiple layers of cells that can stretch out and become thinner depending on pressure. Found in the bladder.