This condition can occur anywhere on the body but does have a high predilection for the feet and lower legs. It is generally regarded that this rash is easier to avoid than it is to treat. The best way to avoid it is to become an amateur botanist. Be aware that it is the oil in the plants that cause the rash. This oil is known as urushiol. Exposure to the oil creates a contact dermatitis which is an allergic reaction. Fifteen to thirty percent of the population are immune to the effects. Compare poison ivy to eczema
Below is a picture of this type of dermatitis.
The rash can develop from:
Urushiol oil can remain viable on dead plants and other surfaces for up to five years causing the same skin reaction.
The saying “leaves of three, let them be” will be mentioned in any article on this type of dermatitis. Learn to recognize that three leaved, low to the ground plants may very well be poison ivy. Three-leaved poison oak also grows as a low plant or bush; their leaves resemble oak leaves.
Poison sumac bushes or trees are more common in wet, marshy areas, the difference in the leaves is that each leaf has seven to thirteen shiny, smooth edged leaflets.
If you know you are going to be in an area with poison ivy and incidental contact is a possibility then the best way to protect yourself is by wearing long pants, tucked into your socks, along with a long sleeve shirt. Some sources recommend spraying exposed body parts with deodorant as there is an additive in the deodorant that prevents the poison oil from entering the skin.
Once exposed to the urushiol oil try to wash off the oil with nothing more than soap and water within fifteen minutes or less. If available, lye soap may work somewhat better.
The problem with urushiol oil is that it remains active for a long period of time. All clothing and equipment that came into contact with the oil also has to be cleaned since any lingering oil can also re-infect.
Once you are exposed, a rash will develop in one to two days. At this point treatment is geared to reducing symptoms and preventing blistering and secondary bacterial infection.
In around 12 hours after exposure the first signs will be little bumps that look like insect bites.
Prescription grade topical cortisone cream applied to the area in an effort to reduce the impending inflammation is the best treatment available. Just apply the medicine, allow to air dry. Do not cover with bandages. If prescription cortisone cream is not available to you than over-the-counter hydrocortisone cream or calamine lotion is an acceptable alternative, but still not as effective as prescription medication.
Oral antihistamines may be very helpful to reduce the itch. By scratching the area you increase the inflammation, you may also spread the poison and you may develop secondary bacterial infections due to the breaks that will occur in the skin. This will then require oral antibiotics.
Cool showers and lukewarm baths with oatmeal or baking soda added to the baths may be helpful in reducing the inflammation and drying up the oozing blisters.
The good news is that this condition is a self limiting usually resolving in 14 days, and that during the active phase, any measures you take to reduce the inflammation and itching will go a long way to making your experience that less miserable.