Both shingles and poison ivy cause a painful, blistering rash. Poison ivy is an allergic reaction, while shingles is a viral infection. Shingles also causes additional symptoms that can differentiate the conditions.
The varicella-zoster virus causes chickenpox. After a person has chickenpox, the virus travels from the skin to the nerves and remains dormant.
Sometimes the virus reactivates and travels from the nerves to the skin, causing shingles. This results in a painful, blistering rash.
The Centers for Disease Control and Prevention (CDC) estimates that
Poison ivy is a type of allergic contact dermatitis. It can also cause a painful, blistering rash. The rash is an allergic reaction to urushiol oil, which is in the sap of poison ivy. The oil is also present in poison oak and poison sumac.
According to the American Academy of Dermatology (AAD), it can take 2–3 weeks for the rash to appear if a person has not come into contact with the plant before. This can make it challenging to identify the cause of the rash.
This article explains the difference between the two rashes and other accompanying symptoms. It also explains the different treatments available.
The following table outlines the differences between shingles and poison ivy:
|Cause||varicella-zoster virus||direct contact with the plant|
|Characteristics||• a painful blistering rash that typically develops on |
• blisters tend to be small and develop in clumps
|• a painful rash that develops anywhere skin came into contact with the plant|
• some people develop black spots or streaks instead of a rash, but this is rare
|Additional symptoms||• fever|
• nerve pain
• upset stomach
|no additional symptoms|
|Treatment||• prescription antiviral medication|
• calamine lotion
• colloidal oatmeal baths
• cool compresses
• calamine lotion
• short, lukewarm baths
• hydrocortisone cream
• pain medication
|Prevention||getting the shingles vaccine (the ||• wearing long sleeves and pants when in areas of poison ivy|
• applying a poison ivy blocker to the skin
• washing skin, clothes, and tools after being near poison ivy
One difference is where the rash appears. The AAD explains that while a shingles rash can develop anywhere on the body, it is most common around the trunk. It typically affects just one side of the body.
Poison ivy does not usually cause additional symptoms.
The table below shows what symptoms to look for to help determine the cause of the rash:
|Red, dark, or skin-colored blotches||✓||✓|
Both shingles and poison ivy rashes look similar and follow a similar pattern. Anyone with a blistering skin rash should contact a doctor as soon as possible.
The AAD notes that a shingles rash develops in the following way:
- A few days before the rash develops, a person will experience a painful, burning sensation on the area of the skin where the rash will appear.
- The rash will appear. It typically develops on only one side of the body. Small blisters will develop in clumps.
- The blisters will break open and crust over. It can take 2–4 weeks to clear completely.
Poison ivy rashes can occur anytime a person has contact with the plants. The AAD explains that the first time a person has contact, it can take 2–3 weeks for a rash to appear.
After the first contact, poison ivy rashes usually appear within 4–48 hours.
The rash develops in the following way:
- Before the rash appears, the skin will itch intensely. It can be intense enough to wake up a person at night.
- An itchy, painful, blistering rash appears. The blisters can break open and leak.
- The blisters crust over. The rash usually resolves in 2–3 weeks.
Occasionally, people develop black spots or lines on their skin. Doctors call this black-spot poison ivy dermatitis.
People with shingles can also develop:
- upset stomach
- nerve pain
Although poison ivy does not usually cause additional symptoms, a person who has come into contact with the plant can develop a severe allergic reaction. This can cause:
- difficulty swallowing or breathing
- rash around the eyes, mouth, and on the genitals
- facial swelling
- rashes that cover most of the body
If a person develops any of the above symptoms, emergency medical attention is needed.
The following can help treat the rashes associated with poison ivy and shingles.
Doctors can treat shingles with antiviral medications, including:
These medications are most effective when a person takes them within 3 days of the rash appearing. While they do not cure the illness, they may shorten the duration and severity of the infection and ease the pain.
People can also try:
- taking over-the-counter pain medications
- applying cool compresses
- applying calamine lotion
- taking colloidal oatmeal baths
For poison ivy, the AAD recommends washing the skin in lukewarm soapy water as soon as possible after exposure to remove the urushiol oil.
Urushiol oil can stick to surfaces, including pet fur, gardening tools, and clothing, so it is essential to wash all of these thoroughly to remove all traces of the oil.
To help relieve the itch, a person can:
- take short, lukewarm baths
- use calamine lotion
- apply hydrocortisone cream
- take antihistamine pills
While pets are not usually sensitive to poison ivy, urushiol oil can get trapped on their fur. Anyone petting them may transfer the oil to their skin and clothing.
If a pet has come into contact with poison ivy, the FDA suggests bathing them while wearing gloves.
Shingles and poison ivy both cause painful skin rashes, but their causes are different. Shingles is a viral infection, while poison ivy is a type of allergic contact dermatitis.
Although the rashes look similar, people with shingles usually experience additional symptoms, including fever, headaches, chills, and nerve pain.
Anyone who thinks they have shingles should contact a doctor as soon as possible. Prompt treatment with antiviral medications may reduce the severity and length of infection.