Causes
- The cause of a localized rash usually is just from skin contact with something. Examples are rashes caused by chemicals, allergens, or insect bites. Ringworm fungus or bacteria can also cause rashes. It's never a food or drug reaction.
- Irritant dermatitis.
Skin contact with an irritant (such as a harsh chemical). This is the most common cause of new localized rashes. Usually, it's not itchy. If it's just on the fingers, it's usually due to a soap or hand cream. Rubber gloves can also be a cause.
- Contact dermatitis.
Skin contact with an allergic substance. If the rash is very itchy, the cause is probably this. The location of the rash may suggest the cause:
- Poison ivy or oak.
Exposed areas, such as the hands.
- Nickel (metal).
Anywhere the metal has touched the skin. (Neck from necklaces, earlobe from earrings, or fingers from rings. Stomach from metal snap inside pants, wrist from watch, or face from eyeglass frames.)
- Preservatives
in creams, lotions, cosmetics, sunscreens, shampoos: where applied
- Neomycin
in antibiotic ointment: where applied
- Contact dermatitis usually is an allergic reaction. It lasts 2 to 3 weeks. Most contact dermatitis needs a prescription steroid cream to control itching.
Localized Rashes That Are Easy to Diagnose
- Athlete's Foot (itchy pink rash between the toes)
- Impetigo (infected small sores covered by soft yellow scabs)
- Mosquito Bites
- Poison Ivy
- Ringworm (round pink patch that slowly gets bigger)
