Dermatology

Question 1

Functions of the skin

Answer 1

Protection, metabolising vitamin D, control of temperature, reception of sensation, appearance

Question 2

Structure of the skin

Answer 2

Epidermis-superficial layer, main cell type is keratinocyte
Basement membrane - allows epidermal and dermal relationship, prevents infection coming from epidermis to go into dermos
Dermis- provides blood supply to the epidermis

Question 3

Dental implications of psoriasis

Answer 3

Joint involvement may affect OH
Can have erythema migrans like lesions in the mouth
Can affect lips etc

Question 4

Eczema and dentistry

Answer 4

Eczema may affect face and lips
If pt are on steroids- may require steroid cover

E.g. on lips- oedematous areas with spliting

Question 5

Erythema multiforme

Answer 5

Immune complex deposition in the mucosae and skin resulting in inflammatory erythematous conditions.
Can be associated with herpes simplex, some drugs, CT diseases….
If it is associated with systemic fever and significant oral and lip ulcers- Steven-Johnson syndrome.

Question 6

Squamous cell carcinoma

Answer 6

Malignant tumours derived from epithelial cells -e.g. keratocytes

Characterised by ulcerated/modulated lesions with malignant cellular changes (seen histologically). Malignant cells penetrate into the basement membrane and allow spread via blood and lymphatics to regional and distant sites.

Risk factors are sun exposure, immunocompromised pt, pre existing conditions

Question 7

Basal cell carcinoma

Answer 7

Malignant cells are in the basal cell layer in the epidermis
Can grow but rarely metastasized
Appearance- nodular lesion with dilated surface vessels and pearl like edge. Surgical excision usually, but rarely radiotherapy

Question 8

Malignant melanoma

Answer 8

Derived from melanocyte cell in the basal layer of the epidermis
Sun exposure is the biggest risk as well as family history, pre existing moles…
Has ability to metastasise early so very dangerous

Alert if:
Increases in size, change in shape/colour
Diameter more than 5 mm
Inflammation
Itching
Bleeding

Four varieties:
Superficial spreading
Nodular
Lentigo maligna melanoma
Acral

Treatment can be challenging -surgical excision with a margin of at least 1 mm