Dermatology Flashcards
What is the classic presentation of a dermoid cyst?
= cystic teratoma - tumour of mature skin cells; contains skin, sweat glands, hair follicles; sometimes teeth, fat, bone, thyroid tissue. commonly occurs in young child at lateral aspect of eyebrow
What investigation might be required for dermoid cysts and why?
if appears close to midline - to look for intracranial extension if excision considered
What are the commonest histological findings in seborrhoeic keratosis?
localised proliferation of basal layer of epidermis
What are the characteristic features of a sebaceous cyst?
considered same as epidermoid cyst (type of trichilemmal cyst) - closed sac/cyst with lining resembling upper part of hair follicle, produces sebum, may have visible punctum
What is the management of the following manifestations of herpes simplex virus?
- gingivostomatitis: oral aciclovir, chlorhexidine mouthwash
- cold sores: topical aciclovir (?limited benefit)
- genital herpes: oral aciclovir
What is the guidance for herpes simplex infection during pregnancy?
- elective caesarean if primary attack of herpes >28 weeks gestation
- pregnant + BG recurrent herpes: suppressive therapy, reassure low risk of fetal transmission
What organism causes pityriasis versicolor?
Malassezia furfur
What are the features of pityriasis versicolor?
- red when occur in white skin, paler than surrounding skin on brown/black skin
- more noticeable following sun tan
- scale common
- may be itchy
What is first line treatment for pityriasis versicolor?
ketoconazole shampoo - useful for covering large surface area of body
What viruses causes Kaposi’s sarcoma?
Human herpes virus 8
What is the treatment of kaposi’s sarcoma?
radiotherapy + resection
Do most melanomas arise in normal skin or pre-existing moles?
most in normal skin
What is the treatment of acute urticaria?
- First line - non-sedating antihistamine (cetirizine, loratidine, fexofenadine)
- if inadequate response to treatment - doubel standard dose of antihistamine / switch to alternative / use sedating AH at night
- If severe/resistant - prednisolone + AH
What makes incisions less likely to cause keloid scars?
Making incisions along relaxed skin tension lines
What are two options for the treatment of keloid scars?
Intra-lesional steroids e.g. triamcinolone injection
Excision - but be wary may create more scars
What treatment options exist for a port wine stain?
cosmetic camouflage or laser therapy
What are 3 genetic factors that play a role in psoriasis?
- HLA-B13
- HLA-B17
- HLA-Cw6
What immunological factors play a role in psoriasis?
T helper cells, Th17, which produce IL-17 - stimulates keratinocyte proliferation
What is the most common subtype of psoriasis?
plaque psoriasis
What are 4 types of psoriasis?
- plaque psoriasis
- flexural psoriasis (smooth)
- guttate psoriasis (triggered by strep)
- pustular psoriasis (palms + soles)
What are the diagnostic criteria for malignant melanoma?
Glasgow 7 -
3 major: change in size, shape and colour
4 minor: diameter >7mm, inflammation, oozing/bleeding, itch/ odd sensation
What are the commonest sites for melanoma in males vs females?
Males - trunk
Females - lower leg
What 2 dermatological side effects may be seen on the face from anabolic steroids?
- acne conglobata - severe form of acne with burrowing + interconnecting abscesses, irregular scars (keloidal and atrophic)
- acne fulminans - severe, painful, haemorrhagic acne
What are 6 treatment options for actinic keratoses?
- Topical fluorouracil (2-3 week course)
- Topical diclofenac
- Imiquimod
- Cryotherapy
- Curettage
- Cautery