Drug eruptions

Question 1

How common are drug eruptions?

Answer 1

30% adverse reactions are cutaneous

Question 2

Who should be considered as having had a drug eruption?

Answer 2

Any patient taking medication who suddenly develops a symmetric eruption which usually resolves when the drug is withdrawn

Question 3

What is the most common type of drug eruption? What type of hypersensivity reaction is this?

Answer 3

Exanthematous drug eruptions (90%)

Type IV

Question 4

What are indicators of severity in an exanthematous drug reaction?

Answer 4

Involvement of face/mucous membranes
Facial oedema
Confluent and widespread eyrthema
Fever
Lymphadenopathy
Arthralgia
Shortness of breath

Question 5

What accounts for the remaining 10% of drug reactions?

Answer 5

Urticarial- usually IgE-mediated hypersensitivity

Question 6

How do fixed drug eruptions present?

Answer 6

Red, painful, well-demarcated discoid plaques which resolve with permanent pigmentation, and may arise in same position upon subsequent exposure
Usually around lips, genitalia, hands

Question 7

How do severe cutaneous adverse reactions present? Give examples

Answer 7

Cutaneous and systemic symptoms:

• blistering, ulceration
• fever, malaise, arthralgia, myalgia

Toxic epidermal necrolysis
(Stevens Johnson syndrome is a form of TENS)
Drug reaction with eosinophilia and systemic symptoms (DRESS)

Question 8

How do phototoxic drug reactions present?

Answer 8

Prickling, erythema, exaggerated sunburn, telangiectasia,

skin fragility

Question 9

How are adverse cutaneous drug reactions managed?

Answer 9

Discontinue drug
Steroids
Antihistamines
Allergy bracelets may be useful for certain common drugs