Erythema multiforme

(EM)

Erythema multiforme is a serious

of acute, self-limited, recrudescent an

d inflammatory dermatopathy charac

terized by erythema, papula and bliste

r, which involves of skin and mucosa.

DefinitionDefinition

1. Hypersensitivity with infection:

virus, mycoplasma, bacterium, myc

etes or protozoon

2. Food allergy

3. Climatic change

4. Drug allergy (drug eruption)

5. Connective tissue diseases

Etiopathogenisis

Possible mechanism is hyp

ersensetivity of small vessel

es to some sensitizers.

Pathogenesis

1. Lesions ： erythema, papula, blister, b

ulla or blood bister. The mark lesion is i

ris-like lesion.

2. Distribution ：Predilection sites include back of hand, d

orsum of foot, face and cervix. Mucosa c

an be involved.

Clinical ManifestationClinical Manifestation

Idio-EM:etiology unknown

Symptomatic EM:etiology k

nown

Grouping:according to

appearance

Macule typePapule typeBlister type

Macule Type Bright red edematous macule ,round or o

rbicular-ovate. The macule may expand peri

pherad with gloom prunosus center and rub

y-red margin. If central edema is absorbed a

nd depressed like a disk, the lesion will offer r

ing shape. Several ring-shape lesion may conf

luens together to polynucleation.

Papule Type It’s the most common type. Because of s

erosity exudation,the papule swell up to the

surface of skin , dome shape and soybean siz

e ， sometimes like wheal.

Blister Type Severe exudation. The center of rash is b

lister ,surrounding with kermesinus areola. I

t’s called iris-like lesion if different colors an

d sizes of loops overlapped ， like iris. It is

more serious when bulla or blood blister occ

ur.

Mucosal DamageGeneral damage is gray patch,

then blister, erosion, bleed, ulcer

and scab. When in eye,

conjunctivitis is more frequent.

Early lesions include dropsy of upper stra

tum of dermis, vasodilatation swell o

f vessel wall, and perhaps, fibrinoid degenera

tion. The dermal infiltrate is largely lymphocy

te, eosinophile granulocyte, neutrophil.

The blisters lie in the dermal-epidermal juncti

on, or in basal cells.

HistopathologyHistopathology

Hemogram: anemia, leukocytosis (some

times leukopenia ) ,eosinophile granulocyte i

ncrease

ESR: increase

Hemoculture: negative

Sometimes proteinuria and hematuria.

Laboratory Laboratory examinationexamination

Evidence for diagnosis ：1. Pleomorphism

2. Predilection: distal extremities and face, etc.

3. Both skin and mucosa could be involved.

EM must be distinguished from herpetiform dermati

tis and pemphigoid.

Diagnosis and Diagnosis and Differential DiagnosisDifferential Diagnosis

Medication:1. Search for reasons so that corresponding treatment c

an be given. Stop all doubtful allergized medicine.

2. The treatment of EM is determined by type, pathogen

etic condition and diseased region. Antihistamine drugs

are generally chosen.

3. In severe cases, systemic steroid combined with antibi

otics may be used, even supportive care such as blood tr

ansfusion or high protein diet when necessary.

TreatmentTreatment

External:1. Skin erythema , papula ： calamine lotion or catapasm:

Bulla: suck the liquid

Erosion and effusion : hydropathic compress with 3 ％ bo

ric acid solution or Pow. Neomgcin-coal-tar.

2. Oral mucosa erosion: Rinse the mouth with 2 ％ NaH

CO3 ， then repaste Pow.Qingdai, Pow. Xilei,

Cream. mucosal Ulcer or dental ulcer film coating , etc.

3. Ocular damage: Flush with NS ， then apply oculentum ac

idi borici or Cortisone eyewater, etc. It is necessary to pre

vent conglutination, secondary infection ,corneal ulcer an

d perforation, etc.