Dermatology

Question 1

SJS causes

Answer 1

Causes
penicillin
sulphonamides
lamotrigine, carbamazepine, phenytoin
allopurinol
NSAIDs
oral contraceptive pill

Question 2

Topical eflornithine is the treatment of choice for facial hirsutism

Answer 2

Ferriman-Gallwey scoring system: 9 body areas are assigned a score of 0 - 4, a score > 15 is considered to indicate moderate or severe hirsutism

Question 3

Livedo reticularis describes an purplish, non-blanching, reticulated rash caused by obstruction of the capillaries resulting in swollen venules.

Causes

Answer 3

idiopathic (most common)
polyarteritis nodosa
systemic lupus erythematosus
cryoglobulinaemia
antiphospholipid syndrome
Ehlers-Danlos Syndrome
homocystinuria

Question 4

Urinary histamine is used to diagnose systemic mastocytosis

Question 5

A skin biopsy is used to diagnose dermatitis herpetiformis

Question 6

Acanthosis nigricans .

Answer 6

associated with insulin resistance, which can occur in conditions such as obesity, polycystic ovary syndrome and hypothyroidism.

gastric adenocarcinoma (often called malignant acanthosis nigricans

Question 8

Keloid scars - more common in young, black, male adultsl

Question 9

Onycholysis

Answer 9

Causes
idiopathic
trauma e.g. Excessive manicuring
infection: especially fungal
skin disease: psoriasis, dermatitis
impaired peripheral circulation e.g. Raynaud’s
systemic disease: hyper- and hypothyroidism

Question 10

The following factors may exacerbate psoriasis:

Answer 10

trauma
alcohol
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids

Streptococcal infection may trigger guttate psoriasis.

Question 11

Acne rosasea Rx

Answer 11

mild-to-moderate papules and/or pustules
topical ivermectin is first-line
alternatives include: topical metronidazole or topical azelaic acid

moderate-to-severe papules and/or pustules
combination of topical ivermectin + oral doxycycline

Question 12

**** typically lasts for 4-6 weeks, can develop after a flu-like illness, is associated with multiple erythematous lesions affecting the limbs, and is associated with pregnancy. Lesions are often nodular and tender, and the rash is self-terminating. It is often accompanied by arthralgia.

Answer 12

Erythema nodosum

Question 13

Otitis externa and blepharitis are common complications of

Answer 13

seborrhoeic dermatitis

Question 14

***** can cause irreversible skin pigmentation and is now considered a second line drug in acne

Answer 14

Minocycline

Question 15

Eczema Rx

Answer 15

Topical steroids
moderate: Clobetasone butyrate 0.05%
potent: Betamethasone valerate 0.1%
very potent: Clobetasol propionate 0.05%

Question 16

Benztropine or procyclidine may be used to manage an *****

Answer 16

oculogyric crisis

Question 17

Amiodarone can cause corneal opacities

Question 18

an autoregulatory phenomenon where thyroxine formation is inhibited due to high levels of circulating iodide

Answer 18

Wolff-Chaikoff effect

Question 19

Calculated osmolality

Answer 19

This is calculated by the equation (2 x Na+ )+ glucose + urea.

osmolar gap - the difference between the calculated osmolarity and the serum osmolality, normal value is <10

The normal anion gap is between 8 and 14 mmol/L.

Question 20

***** - used in ethylene glycol and methanol poisoning - competitive inhibitor of alcohol dehydrogenase

Answer 20

Fomepizole

Question 21

Cocaine can induce preterm labour

Question 22

Humanising is a process that decreases the immunogenicity of non-human derived monoclonal antibodies

Answer 22

Many monoclonal antibodies are produced in other animals, such as mice, via hybridoma technology (whereby a B cell clonal neoplasm capable of secreting the antibody of interest is introduced into the mouse). Murine-derived antibodies differ significantly enough in the protein structures of their constant and variable regions to be immunogenic to humans. The process of humanisation involves changing the antibody’s constant region, and as much of its variable region as possible to reflect the protein structure of human antibodies, whilst still preserving antigenic specificity. This decreases the immunogenicity of the antibody.

Question 23

It was previously thought that ‘fast acetylators’ were more at risk of isoniazid than other patients. Recent research now suggests however that slow acetylators are actually more likely to suffer hepatotoxicity.

Answer 23

Acetylator status

50% of the UK population are deficient in hepatic N-acetyltransferase

Drugs affected by acetylator status
isoniazid
procainamide
hydralazine
dapsone
sulfasalazine

Question 24

Dry skin is the most common side-effect of isotretinoin

Question 25

Severe acne rosasea Skin thickening around the nose, rhinophyma

Answer 25

Topical ivermectin + oral doxy

Question 26

monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1-3 mm in diameter are typically seen.

Answer 26

Eczema herpeticum

Question 27

Eczema herpeticum is a primary infection of the skin caused by herpes simplex virus (HSV) and uncommonly coxsackievirus

Question 28

Human Herpesvirus-8 is the cause of Kaposi's sarcoma in the immunocompromised host, and possibly Castleman's disease in the immunocompetent adult.

Answer 28

Primary infection in adults features mild symptoms and only a localised rash. In children, the primary infection may cause a fever and maculopapular rash.

Question 29

****** is a rare, slow-growing dermal neoplasm that arises from fibroblasts. It typically presents as a firm, raised nodule on the trunk or extremities and has a high local recurrence rate after surgical removal.

Answer 29

Dermatofibrosarcoma protuberans (DFSP)

Question 30

several violaceous, polygonal papules and plaques with some overlying white scale, on the palms and flexor surfaces of the arms. Close examination of the hands also reveals mild oncodystrophy.

Answer 30

Lichen planus

Question 31

Acute onset of tear-drop scaly papules on trunk and limbs → ?guttate psoriasis

Question 32

Acral lentiginous melanoma: Pigmentation of nail bed affecting proximal nail fold suggests melanoma (Hutchinson's sign)

Question 33

Renal transplant patients - skin cancer (particularly squamous cell) is the most common malignancy secondary to immunosuppression

Question 34

Eczema herpeticum is a primary infection of the skin caused by herpes simplex virus (HSV) and uncommonly coxsackievirus

Answer 34

The history and examination points towards a diagnosis of eczema herpeticum, which requires admission for treatment with intravenous aciclovir. The correct answer here is herpes simplex viruses 1 and 2. Less commonly, it can be caused by coxsackievirus A16.

Question 35

Pytriasis versicolar Rx

Answer 35

Management topical antifungal. NICE advises ketoconazole shampoo as this is more cost effective for large areas if failure to respond to topical treatment then consider alternative diagnoses (e.g. send scrapings to confirm the diagnosis) + oral itraconazole

Question 36

This patient has a classic description of guttate psoriasis. Whilst this will usually self-resolve, ultraviolet B phototherapy has been known to accelerate resolution.

Question 37

****** is associated with seborrhoeic dermatitis

Answer 37

HIV and Parkinson’s disease

Question 38

Describes symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin.

Answer 38

Acanthosis nigricans Causes obesity type 2 diabetes mellitus polycystic ovary syndrome Cushing's syndrome acromegaly hypothyroidism familial Prader-Willi syndrome gastrointestinal cancer drugs combined oral contraceptive pill nicotinic acid Given this patient's age and the rapid onset of his presentation, it is likely that this patient has malignant acanthosis nigricans. Symptoms of pruritis and the presence of more extensive lesions involving the palms, soles and mucosa is more typical of malignant acanthosis nigricans.

Question 39

Grave's disease, orange peel shin lesions -

Answer 39

pretibial myxoedema

Question 40

TEN rx

Answer 40

In patients with an acute rash where toxic epidermal necrolysis is suspected all medication should be stopped and the patient should be transferred to a burns unit. This rash is characterised by epidermal detachment affecting >30% of body surface area mucous membrane involvement and a positive Nikolsky sign.

Question 41

Autosomal recessive conditions are 'metabolic' - exceptions: inherited ataxias Autosomal dominant conditions are 'structural' - exceptions: Gilbert's, hyperlipidaemia type II

Question 42

The condition shows complete penetrance, meaning that everyone who inherits the mutated gene will develop the disease if they live long enough

Answer 42

Huntingtons disease

Question 43

HHV

Answer 43

Pityriasis rosea is associated with the reactivation of herpesviruses 6 and 7. Influenza viruses and vaccines have triggered pityriasis rosea in some cases. The herald patch is a single plaque that appears 1-20 days prior to the generalised rash of pityriasis rosea. Human herpesvirus virus 2 (HHV-2) also commonly known as herpes simplex virus-2 (HSV-2) causes oral and/or genital herpes, therefore this is the incorrect answer in this case. Human herpesvirus virus 3 (HHV-3) also commonly known as varicella-zoster virus (VZV) causes chickenpox and shingles, therefore this is the incorrect answer in this case. Human herpesvirus virus 4 (HHV-4) also commonly known as Epstein-Barr virus (EBV) causes Epstein-Barr virus-associated lymphoproliferative diseases, therefore this is the incorrect answer in this case. Human herpesvirus virus 8 (HHV-8) also commonly known as Kaposi's sarcoma-associated herpesvirus causes Kaposi's sarcoma, therefore this is the incorrect answer in this case.

Question 44

Livedo reticularis, describes an purplish, non-blanching, reticulated rash caused by obstruction of the capillaries resulting in swollen venules.

Answer 44

idiopathic (most common) polyarteritis nodosa systemic lupus erythematosus cryoglobulinaemia antiphospholipid syndrome Ehlers-Danlos Syndrome homocystinuria

Question 46

as a marker for carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis in Han Chinese. Stevens-Johnson syndrome and toxic epidermal necrolysis is a delayed-hypersensitivity reaction, thus involving T-cells.

Answer 46

HLA allele B*1502

Question 47

SJS causes

Answer 47

Causes penicillin sulphonamides lamotrigine, carbamazepine, phenytoin allopurinol NSAIDs oral contraceptive pill

Question 48

Isotretinoin adverse effects

Answer 48

teratogenicity - females MUST be taking contraception low mood dry eyes and lips raised triglycerides hair thinning nose bleeds

Question 49

Pitryasis Rosea

Answer 49

HHV-7 herpes hominis virus

Question 50

Desmoglein 3

Answer 50

Pemphigus vulgaris

Question 51

Hemidesmosomal BP antigens

Answer 51

Bullous pemphigoid

Question 52

******are also psychocutaneous manifestations. These similarly result in skin lesions from picking and excoriating, but patients actively admit their own involvement in creating the lesions.

Answer 52

Neurotic excoriations

Question 53

Linear, well-demarcated skin lesions that appear suddenly, with 'la belle indifference' → ?

Answer 53

dermatitis artefacta

Question 54

Of the non-sedating antihistamines there is some evidence that cetirizine causes more drowsiness than loratadine

Question 55

Scarring alopecia

Answer 55

trauma, burns radiotherapy lichen planus discoid lupus tinea capitis*

Question 56

Drugs causing non scarring alopecia

Answer 56

drugs: cytotoxic drugs, carbimazole, heparin, oral contraceptive pill, colchicine nutritional: iron and zinc deficiency

Question 57

staphylococcal scalded skin syndrome does not involve the mucosal surfaces, whereas SJS does.