Poison Oak Rash on the Arm

Poison oak rash on the arm. Several plants produce toxins that cause skin reaction. This is the appearance of poison oak dermatitis. Note the typical linear streaks produced either by scratching or brushing against the plant. (Courtesy of the Centers for Disease Control.)

Latex Allergy

Allergy to latex products may manifest itself in simple dermatitis, or in a more serious whole body reaction, anaphylaxis. The term "dermatitis" describes an inflammatory response of the skin, caused by contact with allergens or irritants such as the latex in surgical gloves or condoms. Contact with latex may produce an itchy rash, redness, blisters and scaling, or may cause the more severe anaphylaxis. Anaphylaxis is a series of symptoms including dropping blood pressure, swelling of the throat and tongue and difficulty breathing.

Poison Plants

The term "dermatitis" describes an inflammatory response of the skin, caused by contact with allergens or irritants, exposure to sunlight, or by poor circulation, even stress. An example of contact dermatitis is the reaction of a sensitive person's skin to poison ivy, oak or sumac. Contact with these plants, which contain a chemical called urushiol, produces an itchy rash, redness, blisters and scaling. AVOID SCRATCHING. Scratching the rash may spread the inflammation, lead to infection and even leave scars.

Dermatitis, Nickel on the Sole

The metal, nickel, can cause inflammation (erythema), rash, and itching. Nickel dermatitis is relatively common, and can be seen on the wrist from the stainless backs of watches, on the earlobes from nickel plated earrings, or elsewhere on the body from snaps. This person was in contact with something made of nickel or containing nickel salts.

Dermatitis, Contact

This picture shows a skin inflammation (dermatitis) caused by contact with a material that causes an allergic reaction in this person. Contact dermatitis is a relatively common condition, and can be caused by many substances.

Dermatitis, Close-Up of Allergic Contact

This is an example of an allergic skin reaction (allergic dermatitis) caused by hair dye. The skin on the neck is red (erythematous), thickened (lichenified), scaly, and crusted.

Dermatitis, Contact on the Cheek

This picture shows a person with a skin inflammation (dermatitis) on the cheek caused by contact with a substance that produced an allergic reaction (allergen). Contact dermatitis causes redness, itching, and small blisters (vesicles).

Dermatitis, Pustular Contact

This is a close-up of a dermatitis reaction. It consists of a large, red (erythematous) lesion (plaque) with numerous small pus-filled areas (pustules).

Poison Ivy on the Knee

This is a typical early appearance of a poison ivy rash, located on the knee. These early lesions consist of multiple small blisters (vesicles), often in a line where the skin has brushed against the poison ivy plant. The person may then spread the toxin to other areas of the body by scratching.

Poison Ivy on the Leg

This is a typical early appearance of a poison ivy rash, located on the leg. These early lesions consist of multiple small blisters (vesicles), often in a line where the skin has brushed against the poison ivy plant. The person may then spread the toxin to other areas of the body by scratching.

Phytophotodermatitis on the Hand

This person is sensitive to chemicals used in perfumes, and now develops a rash when the area is exposed to light (Phytophotodermatitis). These perfumes include Oil of Bergamot, an oil also found in some citrus fruits and wild plants. It results in streaky redness (erythema) and pigmentary changes.