19 Skin and its Pathology

Question 1

Objectives

Answer 1

Normal skin - structure and function

Common pathologies

Question 2

Functions

Answer 2

Largest organ of the body
Protective barrier against environmental insults
Temperature and water loss regulation
Sensation
Vitamin D synthesis
Appearance

Question 3

Common Terminology

Answer 3

Macule: A flat area of altered colour 0.5cm

Plaque: Palpable scaling raised lesion >0.5cm in diameter

Papule: Solid raised lesion 0.5cm in diameter with a deeper component

Vesicle: Raised, clear fluid-filled lesion 0.5cm in diameter

Question 4

Pathology

Answer 4

Benign lesions

Malignant lesions

Inflammatory conditions

Question 5

Benign Lesions

Answer 5

Skin tags
Moles
Cysts
Papillomas

Question 6

Fibroepithelial Polyps

Answer 6

Common
Generally in middle-age and older people
Neck, trunk, face, axilla and groin
Flesh coloured bag like lesion

Question 7

Naevi

Answer 7

Proliferation of melanocytes (pigment-producing cell)
Naevus cells within the
dermo-epidermal junction (junctional naevi)
dermo-epidermal junction and dermis (compound naevi)
just in dermis (intradermal naevi)

Question 8

Sebaceous Cyst”

Answer 8

Clinical term encompasses 2 types of cysts
Derived from invagination of epithelium

2 types:
Epidermoid cyst
Pilar cyst

Question 9

Seborrhoeic Keratosis

Answer 9

Middle aged and older people

Arise spontaneously

Trunk, head and neck

Question 10

Haemangioma

Answer 10

Benign vascular tumours of the dermis

Tend to occur in children

Bluey red surface

Question 11

Malignant Lesions

Answer 11

Basal cell carcinoma (BCC)
Squamous cell carcinoma (SCC)
Bowen’s disease
Melanoma

Question 12

Basal Cell Carcinoma

Answer 12

Most common human cancer
Slow growing tumours
Rarely metastasize
Occur at sun exposed sites

Question 13

Bowen’s Disease

Answer 13

Precursor to SCC
Epidermal dysplasia
Sun damage

Question 14

Squamous Cell Carcinoma

Answer 14

Second commonest skin tumour of sun-exposed sites in older people

Question 15

Melanoma

Answer 15

Fairly common
Arises in sun damaged skin
Can be very aggressive and spread widely
Used to be universally fatal but early diagnosis means can be removed

Question 16

Melanoma

Answer 16

Asymmetry
Border - irregular
Colour - variable pigmentation in lesion
Diameter - mostly >6mm
Enlarge

Question 17

Rashes

Answer 17

Inflammatory skin reactions
Eczema
clinical term that encompasses many different conditions
literally means “to boil over”
itching, burning, rash, blisters

Question 18

Psoriasis

Answer 18

Commonly affect elbows, knees, scalp, lumbosacral area and glens penis.
Can be associated with nail changes, arthritis, myopathy, enteropathy and spondylic joint disease.
Well demarcated, salmon pink plaques with silver scaling

Question 19

Scabies

Answer 19

common and very itchy
caused by human scabies mites.
common in the young and the elderly.
Spread by direct skin-to-skin contact with someone who already has scabies.
mites are found mainly in the web spaces of the fingers and on the palms of the hands, the wrists, ankles and soles of the feet.
Burrows appear as small greyish lines on the skin

Question 20

Skin in Systemic Disease

Answer 20

Meningitis
SLE
Internal malignancy

Question 21

Meningitis

Answer 21

Unwell (headache, stiff neck, dislike of bright light)
Can deteriorate rapidly (aching limbs (particularly leg pain), cold hands and feet).
The majority (over 50%) with meningococcal septicaemia develop a rash of tiny ‘pink prick’ spots which can rapidly develop into purple bruising.
Non blanching rash

Question 22

Summary

Answer 22

Normal skin
Benign – skin tags, moles, naevi, cysts
Malignant- BCC, Bowen’s, SCC, melanoma
Rashes and skin in systemic disease