Dermatology

Question 1

What are petechiae?

Answer 1

Pin-point, non blanching spots that measure less than 2mm in size and affect the skin and mucous membranes.

Question 2

What does blanching mean?

Answer 2

Skin remains pale for longer than normal when pressed.

Question 3

What is purpura?

Answer 3

Purpura is the name given to the discolouration of the skin or mucous membranes due to haemorrhage from small blood vessels.

They look like small purple spots.
Non-blanching rash

Question 4

Causes of purpura in children

Answer 4

• Meningococcal septicaemia
• Acute lymphoblastic leukaemia

Question 5

Causes of purpura in adults

Answer 5

• Immune thrombocytopenic purpura
• Bone marrow failure (secondary to leukaemias, myelodysplasia or bone metastases)

Question 6

Risk factors for squamous cell carcinoma

Answer 6

-excessive sunlight exposure / psoralen UVA therapy
-actinic keratoses and Bowen’s disease
-immunosuppression e.g. following renal transplant, HIV, smoking
-smoking
-long-standing leg ulcers (Marjolin’s ulcer)
-genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism

Question 7

What is dermatitis herpetiformis?

Answer 7

Dermatitis herpetiformis is a chronic, autoimmune, blistering skin disease characterized by intensely itchy papules and vesicles. It is closely associated gluten sensitivity and coeliac disease.

Question 8

What is eczema herpeticum?

Answer 8

Eczema herpeticum is a potentially serious widespread herpes simplex virus infection, which typically affects people with atopic dermatitis, eczema and inflammatory skin conditions.

It typically presents in children, as an eruption of punched out ulcers most commonly affecting the head, neck and trunk at sites of atopic dermatitis.

Question 9

Features of squamous cell carcinoma

Answer 9

-typically on sun-exposed sites such as the head and neck or dorsum of the hands and arms
-rapidly expanding painless, ulcerate nodules
-may have a cauliflower-like appearance
-there may be areas of bleeding

Question 10

Eczema: topical steroids

Answer 10

-use the weakest steroid cream which controls patient’s symptoms

-mild= hydrocortisone
-moderate= betamethasone valerate, clobetasone butyrate
-potent= fluticasone propionate, betamethasone
-very potent= clobetasol propionate

-finger tip rule: 1 finger tip= 0.5g, sufficient to treat a skin are about twice that of the flat of an adult hand

Question 11

What is cellulitis?

Answer 11

Cellulitis is a bacterial infection that affects the dermis and the deeper subcutaneous tissues.

Question 12

What is the most common cause of cellulitis?

Answer 12

Steptococcus pyogenes

Question 13

What are the features of cellulitis

Answer 13

-commonly occurs on the shins
-usually unilateral
-erythema
-swelling
-systemic upset- fever, malaise, nausea

Question 14

What is the Eron classification?

Answer 14

A guide to how we manage patients with cellulitis

Question 15

Management of cellulits

Answer 15

-management is guided by the Eron classification

-oral flucloxacillin as first- line treatment for mild/moderate cellulitis