While rare, some people see black spots instead of a red rash on their skin. These spots look like black lacquer spilled onto the skin. Instead of black spots, some people develop black streaks on their skin.
If you develop black spots or streaks, there tends to be little or no redness and swelling. The medical term for this condition is black-spot poison-ivy dermatitis.
Poison ivy rash
A rash from one of these poisonous plants usually shows up as red, itchy bumps on the skin.
Black-spot poison-ivy dermatitis
A few people develop black spots or streaks of black on their skin rather than a red rash.
Poison ivy rash: Streaks and spots
This 7-year-old boy developed red streaks and black spots.
How does the rash show up on the skin?
It takes time for the rash to appear. A rash can develop in a few hours if you’ve had a rash from one of these plants before. If you’ve never had a rash from poison ivy, oak, or sumac, it can take 2 to 3 weeks before you see a rash.
No matter how long it takes for the rash to appear, most people experience the following when they get a rash:
The skin itches intensely where the rash will appear. The itch can be so intense that it wakes you from a sound sleep.
Shortly after your skin starts to itch, the rash appears. Most people develop an itchy, red, and blistering rash.
If you have blisters, they break open and leak fluid.
The blisters crust over, and the rash clears in 2 to 3 weeks. The rash will clear without treatment, but it can be extremely itchy until it clears completely.
The intensity of the itch and severity of the rash can differ from person to person. Some people develop 1 or 2 small rashes. Others develop rashes all over.
Why does the rash from poison ivy, oak, or sumac spread?
While it may look like the rash is spreading, what’s most likely happening is that you’re developing one or more new rashes. This happens because you either:
If your new rash appears near the current rash, it can look like the rash is spreading.
Many people also mistakenly believe that when they touch their rash, they can spread the rash from one part of their body to another. You cannot spread the rash.
If you have oil from the plant on your skin, you can spread the oil for a short time. Your skin absorbs the oil quickly, so you can only spread the oil from one part of your skin to another for a short amount of time.
How long does a rash from poison ivy, oak, or sumac last?
How long you have a rash depends on whether you’ve had a rash from one of these plants before. Here’s the general rule:
If you’re wondering why you develop a rash from these plants, you’ll find the answer at: Poison ivy, oak, and sumac: Who gets a rash, and is it contagious?
Images
Image 1 used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides.
Images 2,3 used with permission of the Journal of the American Academy of Dermatology.
References
Kurlan JG, Lucky AW. “Black spot poison ivy: A report of 5 cases and a review of the literature.” J Am Acad Dermatol 2001;45:246-9.
McGovern TW. “Dermatoses due to plants.” In: Bolognia JL, et al. Dermatology. (second edition). Mosby Elsevier, Spain, 2008: 255-6.
FAQs
A rash from poison ivy, oak, or sumac looks like patches or streaks of red, raised blisters. The rash doesn't usually spread unless urushiol is still in contact with your skin.
What does sumac poison sumac look like? ›
A full-grown poison sumac tree can get up to 20 feet tall. This tall tree has drooping clusters of pale yellow, cream-colored or green berries. Nonpoisonous sumacs have red, upright berries. Contact with nonpoisonous sumacs won't cause an allergic rash.
How long does it take for poison ivy oak and sumac to go away? ›
How long does a rash from poison ivy, oak, or sumac last? Previous rash from poison ivy, oak, or sumac: The rash tends to last 1 to 14 days before it clears on its own.
What are the stages of poison ivy rash? ›
First comes the itching, then a red rash, and then blisters. These symptoms of poison ivy, poison oak, and poison sumac can emerge any time from a few hours to several days after exposure to the plant oil found in the sap of these poisonous plants. The culprit: the urushiol oil.
What kills poison ivy, oak and sumac? ›
Rid worksites of poison ivy, oak, and sumac by spraying the plants with the herbicide, glyphosate, according to label directions. The best time to apply the herbicide is May through July, when poison ivy, oak, and sumac are flowering.
What is the first aid for poison ivy, oak sumac? ›
Place cool compresses on the skin as needed for itching. For itching: Add oatmeal to the bath and put calamine lotion on the skin (but not on the face or on the genitals). Antihistamines aren't usually helpful for the itching from poison ivy, but doctors might recommend them to help itchy kids sleep.
What is the fastest way to cure poison sumac? ›
There is no cure for the rash. You'll have to wait for the symptoms to pass. There are many over-the-counter remedies to help with your symptoms in the meantime, including: calamine lotion.
How to get rid of poison sumac rash quickly? ›
Home Remedies for Poison Ivy, Oak, or Sumac
To help with oozing problems, try over-the-counter creams or lotions that you put on the rash, such as those that contain: Aluminum acetate (Burow's solution) Aluminum sulfate. Calcium acetate.
Is sumac worse than poison ivy? ›
Poison Sumac (Toxicodendron vernix)
More allergenic than poison ivy and poison oak is poison sumac, a deciduous woody shrub or small tree that grows 5–20 feet tall and has a sparse, open form (Figure 9).
What does poison sumac look like on your skin? ›
The Rash Shows Up Right Away
It forms within 24 to 72 hours of contact, depending on where the plant touched you. It usually peaks within a week, but can last as long as 3 weeks. A rash from poison ivy, oak, or sumac looks like patches or streaks of red, raised blisters.
Like other irritations to the skin, air is helpful to healing poison ivy or oak rash so it's best to leave it uncovered as often as you can. If you do cover the rash, use a sterile bandage applied loosely so that oxygen can reach the surface of the skin.
What dries up poison ivy the fastest? ›
Applying rubbing alcohol to a rash can help dry it up and prevent infection. Some other home remedies that act as astringents and can dry up a poison ivy rash include: witch hazel. apple cider vinegar.
What day is poison ivy rash the worst? ›
The symptoms are worse within 1 to 14 days after touching the plant, but they can develop up to 21 days later if one has never been exposed to urushiol before. The blisters can occur at different times in different people; blisters can develop on the arms several days after blisters on the hands developed.
What can be mistaken for poison ivy rash? ›
Poison oak and poison sumac cause a similar rash that can be treated in the same way as poison ivy.
What does a bad poison ivy rash look like? ›
Symptoms of a poison ivy, oak, or sumac rash
Here's what to watch out for: Intense itching is common, often before the rash appears. Raised, red, violet, or brown bumps and blisters are filled with clear fluid form. A rash in lines or streaky patterns appears where the plant touched the skin.
What is more poisonous poison ivy or poison oak or poison sumac? ›
Poison sumac is considered the “most toxic plant in the country.” However, on a positive note, it's also much rarer than the others. It only grows in super wet areas, like bogs or swamps. Just like poison ivy, sumac also contains urushiol. That means it causes the same reaction as poison ivy — an itchy rash.
How to tell the difference between poison sumac and a sumac tree? ›
Poison sumac produces flowers and fruit that are small and greenish-white in color. The key to identifying poison sumac is the number of leaflets on each leaf. Unlike harmless Sumac, which has anywhere from 11 to 31 leaflets, poison Sumac has only 7 to 13 leaflets on each leaf.
Can poison ivy have 5 leaves? ›
Young Virginia creeper leaves or those that have been damaged may occasionally have three leaflets, but most have five (figure 6). Poison ivy never has five leaflets. Plants of both species often have a reddish center where the leaflets join.
