Urushiol is an oil found in poison ivy that may cause an allergic reaction leading to allergic contact dermatitis.
Image credit: Nunyabb, 2006
While most people do not experience a major allergic reaction, the effects of contact dermatitis can be unpleasant until they subside.
When a person's skin comes into contact with an irritating substance, they may develop an itchy or burning rash. This reaction is known as contact dermatitis.
Contents of this article:
Types of contact dermatitis
While contact dermatitis can seem like it develops out of nowhere, there are several common types:
Irritant contact dermatitis is the most common type of contact dermatitis. It happens when the skin touches an irritating chemical, experiences too much friction, or makes contact with heat.
Allergic contact dermatitis is caused by an allergic reaction or by the immune system overreacting to a substance or chemical. Contact urticaria, also known as hives, is a less common type of allergic contact dermatitis that occurs immediately after exposure to an allergen.
Occupational contact dermatitis occurs in certain professions where the workers may come into repeated, frequent exposure to irritants or allergens, such as rubber, latex, or chemicals. These people include healthcare workers, hairdressers, and food servers among many others.
Photocontact dermatitis occurs after a person comes into contact with an irritant or allergen and the area of contact subsequently receives sun exposure that causes a reaction.
In all of these cases, an itchy or burning rash appears either immediately or within a few days. It is important that people treat the rash and know what triggered it in order to avoid contact dermatitis in the future.
Symptoms of contact dermatitis
In nearly all cases of contact dermatitis, a rash will develop after exposure to an allergen or irritant. In most cases of contact dermatitis, the rash will be red, itchy, and may sting. If exposure to an irritant or allergen continues, the skin may become dark and leathery.
Additionally, some types of contact dermatitis have the following symptoms:
- dry, cracked, and flaky skin
- burning sensation
- pain or itching
To distinguish between types of contact dermatitis, a person should pay attention to when the symptoms start.
When contact dermatitis develops due to an irritant reaction, symptoms can occur immediately upon contact with the irritant. Ulcers may also develop in severe cases, which allows the person to identify the triggering irritant.
In cases of photocontact dermatitis, the rash only appears once an individual is exposed to sunlight.
Triggers vary from person to person and according to the type of contact dermatitis. It is important to know what triggers a reaction in order to avoid contact with the substance in the future.
The following are some of the most common triggers for the different types of contact dermatitis.
Allergic reaction triggers include:
Fragrances in soap may be a trigger for contact dermatitis.
- poison ivy, poison oak, and poison sumac
- medications applied to the skin
- fragrances in soap
- the tanning agent found in leather products
- skin cream
- shaving cream
- nickel or gold jewelry
- citrus fruit
- hair dye
In most cases, allergic reactions do not occur on the first contact with the substance. On first contact, the person tends to gain a sensitivity to the irritant. Only with a second exposure will the person develop a rash or other symptoms.
Irritant reaction triggers include:
- pepper spray
- hand sanitizer
- battery acid
- drain and other cleaners
Irritant reactions are not limited to toxic or more corrosive substances.
In some cases, frequent exposure to the same substance causes reactions. For example, people who frequently wash their hands may develop an irritant response to the soap they use.
Photocontact reaction triggers may include:
- shaving cream
- skin ointment
- certain oils
- certain medications
Photocontact reactions occur less often than allergic or irritant reactions.
For the reaction to occur, a person needs to be exposed first to the substance and then to the sun. An individual who uses a cream before bed may never know they are photosensitive to the product because it is absorbed well before contact with the sun.
A home treatment option for contact dermatitis may be antihistamine drugs.
In most cases, the rash and other reactions will disappear after exposure to the substance has ended.
The rash may take some time to heal and fully go away. For example, a rash from poison ivy often lingers because the oils from the plant have seeped into the skin. Once the oil is gone, the rash clears up.
It is best for a person to avoid contact with substances identified as causing contact dermatitis.
If contact is made, it is a good idea to clean the area with some mild soap and water to potentially prevent a rash developing.
Most treatment options involve home remedies. They include:
In extreme cases, a person may need to see a dermatologist, allergist, or other healthcare professional. They can prescribe ointment, creams, or prescription drugs to treat contact dermatitis.
In most cases, prevention is as simple as avoiding the substance or object that caused the contact dermatitis in the first place. For example, a person who develops a rash after coming into contact with poison ivy should try to avoid the plant.
However, a person may not know what caused the reaction. If the exact cause is unknown, a person may want to record things they come in contact with to help determine what might be causing the reaction.
Often, a person may not consider that a change in skin care products may be the source of the irritation.
An allergist may be able to identify the allergen or irritant from a list of substances the person came in contact with over the previous 24 to 48 hours.
In other cases, the allergist can use skin tests to help determine the cause of a reaction.