Shingles or poison ivy?
With more time spent outdoors, there are more chances to encounter poison ivy, poison oak or poison sumac, all of which grow in North Carolina. Contact with the oils from these plants can result in a red, itchy blistery rash which can continue to pop up on different areas of the skin for a couple of weeks. Often the rash appears in straight lines and is usually on exposed areas of skin such as arms, legs and face.
Some people who present with contact dermatitis to plants wonder if it is shingles. How does the dermatologist know the difference?
Shingles or varicella zoster is caused by reactivation of the chicken pox virus, so a past history of chicken pox is helpful, but some people do not remember having chicken pox, or they had a very mild case. Shingles appears as clustered red, tiny blisters following a pattern of a nerve. Because individual nerves are on one side of the body or the other, the rash on the trunk will not cross the midline. It can circle around the entire side, but it stops mid back or mid abdomen. If the blistery rash is on both arms, a cheek and lower abdomen it is most likely not shingles. Shingles can be very painful, or can be mostly itchy. Older patients often are the ones with more pain.
If shingles is treated within 48 hours of onset of symptoms, the duration of rash can be shortened and risk of post herpetic neuralgia (pain after the rash resolve) can be lowered. Without treatment the rash will resolve on its own. Scarring is possible.
Contact dermatitis to plants can be treated with over the counter products such as cool compresses, calamine lotion or oatmeal baths, and oral antihistamines like diphenhydramine. For more severe cases, topical or oral corticosteroids can be prescribed. In a few cases, antibiotics may be necessary if the rash has become infected. It is important to wash any gloves, gardening tools, or pets that may have been in contact with the oils or your skin can be recontaminated and the rash will continue to appear.