Poison Ivy Rash
Poison ivy, poison oak, and
poison sumac are plants that can
cause a skin rash called
allergic contact dermatitis when
they touch your skin.
The rash is caused by
contact with an oil (urushiol)
found in these plants.
Contact dermatitis is
a localized rash or
irritation of the skin
caused by contact
with a foreign
Types of Contact Dermatitis
There are three types of contact
irritant contact dermatitis
allergic contact dermatitis
photo contact dermatitis.
Irritant Contact Dermatitis
− caused by chemical and physical
irritant that damages skin's outer
− Common chemical irritants:
• solvents (alcohol, xylene, turpentine,
• ethylene oxide
• surfactants in topical medications
and cosmetics (sodium lauryl sulfate)
• alkalis (drain cleaners, strong soap)
- Physical irritant contact dermatitis is
commonly caused by low humidity
from air conditioning.
Allergic Contact Dermatitis
− occurs when a substance to which
you're sensitive (allergen) triggers an
immune reaction in your skin.
− Common causes of allergic contact
dermatitis are plants of
the Toxicodendron genus:
- poison ivy
- poison oak
- poison sumac
Photo Contact Dermatitis
− is the eczematous condition which is
triggered by an interaction between
an otherwise unharmful or less harmful
substance on the skin and ultraviolet
− Is usually associated only with areas of
skin which are left uncovered by
clothing, and it can be soundly
defeated by avoiding exposure to
Signs & Symptoms
Only the superficial regions of the
skin are affected in contact
Inflammation of the affected tissue is
present in the epidermis(the
outermost layer of skin) and the
outer dermis (the layer beneath the
Contact dermatitis results in large,
burning, and itchy rashes
Takes several days to weeks to
Allergic dermatitis is usually
confined to the area where the
trigger actually touched the
skin, whereas irritant dermatitis
may be more widespread on the
• Red rash. This is the usual reaction. The rash
appears immediately in irritant contact
dermatitis; in allergic contact dermatitis, the
rash sometimes does not appear until 24–72
hours after exposure to the allergen.
• Blisters or wheals. Blisters, wheals (welts),
and urticaria (hives) often form in a pattern
where skin was directly exposed to the
allergen or irritant.
• Itchy, burning skin. Irritant contact dermatitis
tends to be more painful than itchy, while
allergic contact dermatitis often itches.
Medical treatment usually consists of lotions,
creams, or oral medications.
- may be prescribed to combat
inflammation in a localized area.
- in a cream or ointment form.
- If the reaction covers a relatively large
portion of the skin or is severe, a
corticosteroid in pill or injection form may
Oral antihistamines such
as diphenhydramine (Benadryl,
Ben-Allergin) can also relieve
Prescription antihistamines may be
given if non-prescription strengths
Self-care at home
Immediately after exposure to a known
allergen or irritant, wash with soap and
cool water to remove or inactivate most
of the offending substance.
Weak acid solutions [lemon
juice, vinegar] can be used to
counteract the effects of dermatitis
contracted by exposure to basic irritants.
If blistering develops, cold moist
compresses applied for 30 minutes 3
times a day can offer relief.
Avoid scratching, as this can cause
Calamine lotion and cool colloidal
oatmeal baths may relieve itching.
For mild cases that cover a relatively small
area, hydrocortisone cream in
nonprescription strength may be sufficient.
A barrier cream such as those
containing zinc oxide (e.g. Desitin, etc.)
may help to protect the skin and retain
Allergy testing- patch tests done to
identify the responsible agent and
avoid it. The patient must know
where the irritant or allergen is
found to be able to avoid it.
protective clothing, gloves
or barrier cream should be used
depending on the working