Erythema Multiforme Flashcards
1
Q
Describe the rash you would see in EM minor?
A
- Round erythematous macules (a flat, discoloured area of skin <1cm in diameter)
- Developed into papules (a elevated, solid, palpable lesion <1cm in diameter)
- Progress to target lesions (dark centre with pale oedematous ring, surrounded by darker ring)
- Lesions are polymorphous due to different staging of lesion development
- Excoriation marks due to pruritis
- Start in extensor surfaces of hands and feet and spread proximally to the trunk
2
Q
What type of hypersensitivity reaction causes this rash?
A
Type IV
3
Q
What are causes of this rash?
A
Viruses -
- Herpes Simplex Virus (mostly HSV-1)
Drugs -
- NSAID’s
- Anti epileptics - Barbituates, phenytoin
- Antibiotics - Amoxicillin, ampicillin, sulphonamides, tetracyclines
4
Q
What is erythema multiforme major?
A
- Affects one or more mucous membranes in addition to the skin, most commonly the oral mucosa
- The lesions are more likely to form blisters which can spontaneously burst
- Looks similar to Stevens-Johnson syndrome
5
Q
What are risk factors for EM?
A
Main - - Previous episodes - Herpes Simplex Virus - Mycoplasma pneumoniae Others - - Exposure to causative medications - Hep B, syphilis, EBV, CMV, Lymphoma, Tattoos
6
Q
What prodromal symptoms occur with EM major?
A
- Weakness, painful joints, fevers
- Presents one week prior to cutaneous manifestations
7
Q
What investigations would you undertake?
A
- Clinical findings
- Skin biopsy can be performed if uncertain
- CXR and sputum sample if Mycoplasma suspected
8
Q
What is the management for EM?
A
- Self limiting mostly in 2-3 weeks
- Acyclovir if HSV
- Doxycycline if Mycoplasma
Supportive - - Oral antihistamines and topical steroids to reduce pruritis
- Mouthwashes with antiseptic for oral pain
9
Q
What are complications for EM?
A
- Skin discolouration
- Secondary infection at rash sites
- Eye involvement can cause scarring and reduced visual acuity
