PrintRisk Factors and Causes of Rashes
A personal or family history of allergies or asthma increases the risk for rashes. People who spend a lot of time outdoors are at increased risk for poison ivy, poison oak, and poison sumac; and for rashes caused by insect bites.
Common causes for rashes include the following:
- Allergic reaction (e.g., resulting from an animal allergy, drug allergy, or food allergy)
- Bacterial infection (e.g., impetigo)
- Drug side effect
- Excessive skin rubbing (friction)
- Fungal infections (e.g., athlete's foot, ringworm)
- Insect bites (e.g., tick, flea, spider, mosquito)
- Parasite infection (e.g., scabies)
- Prolonged exposure to heat, moisture, or irritants (e.g., heat rash, diaper rash, contact dermatitis)
Certain medical conditions can result in a rash, including the following:
- Acne (often develops on the face, neck, back, and shoulders)
- Lupus (commonly causes a "butterfly" rash across the cheeks and under the eyes)
- Lyme disease (usually transmitted by the bite of an infected deer tick; causes a "bull's eye" rash)
- Psoriasis (typically causes round, red lesions with sharply defined edges and overlying silvery white scales [called plaques]; usually begins as small spots that progressively involve very large areas)
- Rosacea (often occurs on the forehead, nose, and chin)
