CONTACT DERMTITI

SDone by : Ammar Alsabae

Dermatitis:-

Simply means inflammation of skin.

Classification of dermatitis:-

.

1- Etiological classification:

endogenous exogenous

Endogenous cause: -Atopic dermatitis -Seborrheic dermatitis -Nummular eczema -Dyshidrosis -Asteatotic dermatitis -Pityriasis alba -Stasis eczema -Juvenile plantar dermatitis

Exogenous cause: -Irritant contact dermatitis -Allergic contact dermatitis -Photosensitive dermattitis -Dermatophytid (Infective eczematoid dermatitis).

2- Clinical classification:

Acute Subacute chronic

Acute• - Acute: inflammed edematous and erythematous papulovesicular eruption.

Subacute• - Subacute: there is erythema,visible

scales and crust , hyperpigmentation.

Chronic•- Chronic: there is thickened and

hyperpigmented plaque with lichenification.

CONTACT DERMATITIS

CONTACT DERMATITIS

is a term for a skin reaction or inflammation resulting from exposure to harmful external 0influences

- As allergens (allergic contact dermatitis) - or irritants (irritant contact dermatitis) - Or sunlight (Phototoxic dermatitis) occurs when the

allergen or irritant is activated by sunlight.

Note:-

1- Inflammation of the affected tissue is present in the epidermis (the outermost layer of skin) and the outer dermis (the layer beneath the epidermis)

Types of contact dermatitis

-IRRITANT CONTACT DERMATITIS.

-ALLERGIC CONTACT DERMATITIS.

-PHOTO-SENEITIVITY

IRRITANT CONTACT DERMATITIS

Definition• -Non immunological localized inflammatory reaction

of the skin resulting from exposure to substance that cause irritation or eruption in

most people who come in contact with it.

it accounts for 80% of all contact dermatitis.

SO:• Every one is susceptible for I.C.D.

• Irritant contact dermatitis is a major occupational disease.

No requirement for prior exposure.

The lesion develop at first exposure.

More common in women than in men due to environmental factors, not genetic factors.

Causes:-•Chemichal irritants .•Physical irritants .

Causes:-Chemichal irritants:1-Solvents: as alcohol , acetone or ketones

2- Acids: as hydrochloric acid, nitric acid,sulfuric acid.

3- Soaps and detergents (alkalis) : causes what called hand dermatitis

Cumulative irritant contact dermatitis: common in Health care workers , house wife which wash their hands 20-40 times a day.

4- Rubber gloves:has tiny quantities of chemicals which cause a direct

irritant action on hands.More common in a medical health workers .

5-Many plant leaves : which produce direct skin trauma.

6-Napkin dermatitis: due to urine and feces irritants .

7-Cosmetics :

may irritate sensitive facial skin , e.g : around the eye , lips .

8-Dribble rash : around the mouth or on the chin in a baby and older

children due to licking the cause is saliva, which is alkaline.

Physical irritants:-1-Dry cold air (low humidity ) from air condition may

cause dry irritable skin, the most common cause of PICD .

2-Temperature variation: An increase in temperature (up to 43ºC from 20ºC).

3-Water: Continual exposure to water may produce maceration or repeated evaporation of water from the skin.

4-Dusts and gases: may irritate the skin. As Wood dust, tobacco dust in cigar factories.

5- Plants : many plants can cause PICD .

Severity of irritant contact dermatitis depend on:-

1- Amount and strength of the irritant. 2- Length and frequency of exposure. 3- Skin susceptibility (eg. thick, thin, oily, dry,

previously damaged skin). 4- Environmental factors (eg. high or low temperature

or humidity).

Pathophysiology:-Irritants damage of the skin surface faster than theskin is able to repair the damage .• Detergents, surfactants, extremes of pH, and organic solvents

all directly affecting the barrier properties of the epidermis , and lead to pathophysiological change .

The 4 main pathophysiological changes are:1- skin barrier disruption,2-removing fat from skin allowing the irritants to penetrate

more deeply and cause damage.3- epidermal cellular changes,4- cytokine release.

Types of ICD1- Acute ICD:A single exposure to strong irritant substance causes an acute dermatitis,

within minutes to hours after exposure.

2-Sub acute ICD:

Repeated exposure of small area as in napkin dermatitis.

3- Chronic ICD: ( cumulative)This is due to multiple exposures, often to several irritants at low levels

over time. This dermatitis can take many months or years to appear

Clinical picture

1- Red rash (erythema): This is the usual reaction. The rash appears immediately in irritant contact dermatitis.

2- Dryness of skin.3- Itchy, burning skin: it tends to be more painful than itchy, while

allergic contact dermatitis often itches. 4- Blisters or wheals: forms where skin was directly exposed to the allergen or irritant.5- Rapid onset 4-12 hours after expoure; whereas in allergic contact dermatitis, the rash sometimes does not appear until 24–72 hours after exposure to the

allergen.

6- Occur at sites with direct contact with little extension.

7- often affects the exposed areas as hands, which have been exposed to irritant.

.

In Acute ICD: characterized by pruritus ,erythema ,papules ,blisters wheels..

In Subacute ICD: the lesions are erythmatous with scales and crusting.

In chronic ICD: begins with a few patches of dry skin is very itchy, with redness, scaling , lichenification hyperpigmentation ,fissuring.,

•Diagnosis:-1- From detailed history which required to identify the

causative agent.2- From clinical picture of affected sites.3-Patch tests :Patch tests are used to confirm or exclude allergic

contact dermatitis and identify the allergen.

They do not exclude irritant contact dermatitis as the two may coexist.

Deferential diagnosis:

-AIlergic dermatitis-drug eruption dermatits-atopic dermatitis

-seborrhoeic eczema-discoid eczema -asteatotic eczema -stasis or venous eczema

Prevention and

Treatment

Prevention:

-Avoid the suspected irritant, By use of protective clothing, and gloves.

1-Clean hands 2-Dry 3-Moisturise

-Always keep your hands moister after washing .

Treatment:

1-Chemical burns are usually flushed with water followed by use of antidote against the particular toxic chemical.

2- Emollints cream , They are used to correct dryness and scaling of the skin, and mild irritant contact dermatitis.

3-topical corticosteroids, which suppress the inflammatory reaction so should reduce redness, swelling and pain.

4-Antihistamine treatments for itching.5-Antibiotic, for secondary bacterial infection , (usually

flucloxacillin or erythromycin)

Complications:

1-secondary bacterial infection by Staphylococcus aureus.

2- cosmotic problems : post inflammatory hyperpigmentation or hypopigmentation , Scarring may occur after corrosive agent exposure .

3-neurodermatitis.

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