12. 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.
13. 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)
16. 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.
17. 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.
20. 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.
21. 4- Rubber gloves:
has tiny quantities of chemicals which cause a direct
irritant action on hands.
More common in a medical health workers .
25. 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.
26. 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 .
27. 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).
28. Pathophysiology:-
Irritants damage of the skin surface faster than the
skin 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.
29. Types of ICD
1- 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
30. 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.
31. 6- Occur at sites with direct contact with little
extension.
7- often affects the exposed areas as hands, which
have been exposed to irritant.
.
32. In Acute ICD: characterized by
pruritus ,erythema ,papules ,blisters
wheels..
33. In Subacute ICD: the lesions are
erythmatous with scales and crusting.
34. In chronic ICD: begins with a few
patches of dry skin is very itchy, with
redness, scaling , lichenification
hyperpigmentation ,fissuring.,
35. •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.
40. 1-Clean hands 2-Dry 3-Moisturise
-Always keep your hands
moister after washing .
41. 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)
42. 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.
