cutaneous drug eruptions

Question 1

what does dose dependant mean

Answer 1

Refers to the effects of treatment with a drug. If the effects change when the dose of the drug is changed, the effects are said to be dose-dependent.

Question 2

what drug can induce alopecia

Answer 2

tamoxifen

Question 3

who do you consider when someone has a reaction that you think is drug induced

Answer 3

• any patient taking medication who suddenly develops a symmetrical skin eruption
• usually resolves when teh drug is withdrawn

Question 4

what are risk factors for drug eruptions

Answer 4

• age
• gender: females are more likely
• genetics
• concomitant disease ie viral infections
• immune status eg previous drug reaction or positive skin test

Question 5

wha are risk factors for culprit drugs

Answer 5

• chemistry eg Beta lactam compunds, high molecular weight/hapten-forming drugs
• route - topical v oral/systemic
• dose
• kinetics

Question 6

what are exanthematous drug eruptions

Answer 6

• most common type (90%)
• idiosyncratic, T cell mediated delayed type hypersensitivity (type IV) reatcion
• Exanthematous drug eruption (EDE; also known as morbilliform drug eruption) is the most common of all medication-induced drug rashes. It consists of red macules and papules that often arise on the trunk and spread symmetrically to involve the proximal extremities.

Question 7

what drugs are associated with exanthematous eruptions

Answer 7

• penicillins
• sulphonamides
• erthromycin
• streptomycin
• allopurinol

Question 8

for exanthematous drug erruptions what are indicators of potentially severe reactions

Answer 8

• facial erythema and oedema
• fever
• involvement of mucous membrane and face
• skin pain
• blisters, purpura, necrosis
• lymphadenopathy

Question 9

what are urticarial drug reactions

Answer 9

• usually an immediate IgE mediated hypersenitivity reaction (type 1) after rechallenge with drug or direct release of inflammatory mediators from mast cells on first exposure

Question 10

what are fixed drug erruptions

Answer 10

• well demarcated round plaques
• red and painful
• hands, genetalia, lips, ocasionally oral mucosa
• resolves with persistant pigmentation when drug stopped
• can re-occur at same site on re-exposture to drug
• usually mild when restricted to a single lesion
• can present as eczematous lesions, papules, vesicles or urticaria

Question 11

what drugs are associated with fixed drug eruptions

Answer 11

• tetracycline, doxycycline
• paracetamol
• NSAIDS
• carbamazepine

Question 12

what are cutaneous and systemic symptoms for adverse drug reactions

Answer 12

• stevens johnson syndrome
• toxic epidermal necrolysis
• drug reaction with eosinopilia and systemic sysmptoms
• acute generalised exanthematous pustulosis

Question 13

what are consequences of severe cutaneous drug reactions

Answer 13

• hypothermia
• fluid loss
• protein loss
• sepsis
• multiple organ failure
• permanent sequelae
• death

Question 14

what are phototoxic cutaneous drug reactions

Answer 14

• non-immunological skin reaction due to light activation of a photo reactive drug
• usually UVA/visible light
• idiosyncratic reactions can occur
• increased sensitivity to sunlight, caused by drugs, can also occur via other mechanism eg immunosupression or lupus

Question 15

what are patterns of skin phototoxicity

Answer 15

• immediate prickling with delayed erythema and pigmentation
• exaggerated easy sunburning
• telangiectasia on sun exposed sites
• delayed 3-5 days erythema and pigemtation
• increased skin fragility

Question 16

what drugs are associated with phototoxicity

Answer 16

• antibiotics
• thiazides
• NSAIDS
• Amiodarone
• Quinine