Poison ivy is capable of causing “rhus dermatitis” which is a form of contact dermatitis. This reaction involves irritation of the skin due to exposure to an irritant. In poison ivy plants, it has a resin specifically urushiol which is responsible for the reactions.
Plants that have urushiol
Poison ivy
The characteristics of poison ivy, sumac or oak varies by region and the season. The leaves of the plant are usually in groups of 3 and notched although they can be smooth-edged. The plant typically grows as shrubs or vines.
Poison oak
The leaves of poison oak appear as groups of 3, 5 or 7. They are relatively smaller in appearance than the poison ivy with smooth, rounded edges. Poison oak grows as a small-sized bushy plant or climbing vine.
Poison sumac
Poison sumac has 7-13 leaves on a single stem that is angled upwards. The leaves are smooth-edged, oval-shaped and about 10 cm long.
Vital facts about poison ivy
Poison ivy along with poison sumac and poison oak are capable of causing contact dermatitis upon exposure. Many individuals require medical care after being exposed to any of these plants.
A reaction can occur after contact with the leaf or internal parts of the stem or root of the poison ivy plant. It usually takes approximately 8-48 hours for a rash to occur after exposure to urushiol. The rash is usually red, linear or circular pattern and contains blisters.
It is important to note that urushiol is usually found under the fingernails, on tools and clothing unless removed deliberately. The resin itself is usually in an active state and capable of triggering a fresh rash for up to 3 weeks after being exposed. Urushiol is not present in the blister fluid and could not spread the rash. If not treated, the rash eventually resolves in 3 weeks.
Management of poison ivy rash
The usual sites that are exposed to poison ivy include the legs, arms and the face. The severity of the rash varies depending on the sensitivity level of the individual, extent of exposure and the amount.
- Cleanse or wash the skin using water and soap to inactivate and eliminate the resin. This is effective if done within 15 minutes of exposure.
- Apply a moist, cold compress during the blistering phase. The application must be done 15-30 minutes several times throughout the day during the initial 3 days.
- Short, cool baths in a tub with colloidal oatmeal can provide a soothing effect and control the inflammation.
- The application of steroid ointments or cream can reduce the itchiness and redness. Hydrocortisone can be applied on the face but not strong enough for more severe cases on the legs or arm. These require prescription-strength steroids.
- Calamine lotion can be applied to reduce the itchiness
- Oral steroids can be used for severe cases but should be limited to at least a week of use.
- Antihistamines can be used to minimize the itchiness and even encourage sleep.