Causes of Erythema Multiforme?

Infections – Drug reactions

Infections

Herpes simplex virus (HSV) 1 and 2 infections (account for >50% of cases).

Mycoplasma pneumonia infections.

Fungal infections.

Other viruses (varicella-zoster virus, cytomegalovirus, hepatitis C virus, and HIV).

Drug reactions

Barbiturates.

Penicillins.

Phenothiazines.

Sulfonamides.

Anticonvulsants.

Non-steroidal anti-inflammatory drugs.

Vaccinations (diphtheria-tetanus, hepatitis B, smallpox).

Features of history and examination in Erythema Multiforme

few to hundreds of skin lesions erupt within a 24-hour period.

The lesions are first seen on the backs of hands and/or tops of feet, and then spread along the limbs towards the trunk.

The upper limbs are more commonly affected than the lower.

Palms and soles may be involved.

The face, neck and trunk are common sites.

Skin lesions are often grouped on elbows and knees.

There may be an associated mild itch or burning sensation

Differential diagnosis in Erythema Multiforme

Drug eruptions

SJS

TEN

Contact dermatitis

Urticaria

Urticarial vasculitis

Pityriasis rosea

Pemphigoid

Pemphigus

Investigations in Erythema Multiforme

Skin biopsy potentially

Managament of Erythema Multiforme

If a drug is thought to be responsible, it must be withdrawn.

If an infection is suspected, it should be treated.

Pharmacological Management of Erythema Multiforme

Apply emollient

Topical corticosteroid

Betamethasone Dipropionate 0.05% od 2 weeks

Betamethasone valerate 0.1% ointment once daily 2 weeks

Mometasone Furoate 0.1% daily 2 weeks