Rashes have a variety of causes, such as an underlying medical condition, fever, allergic reaction or general illness, according to MedicineNet. They may also be brought on by viral, fungal, bacterial or parasitic infections.
Contact dermatitis is a common type of rash caused by the skin's reaction to various soaps, chemicals, cosmetics or lotions, reports Healthline. Contact with poisonous plants, such as poison ivy, poison sumac and poison oak is known to cause a severe rash. Eczema is a common rash for those who suffer from allergies or asthma. Some bug bites may cause a rash, particularly tick bites, which also transmit disease.
Infants are prone to diaper rash, which is caused by contact of soiled diapers for too long, explains MedicineNet. Viral rashes are caused by infections such as herpes or shingles, while heat rash is a result of blocked sweat ducts during hot, humid months. Side effects to certain prescription drugs may result in the outbreak of a variety of rashes.
A rash may be caused by other medical conditions, including stress, which can bring on acne and cause psoriasis to flare up, notes Healthline. Hives is a common rash that acts up as a response to stress and allergic reactions, extreme exercise, heat and excessive alcohol use. Self-diagnosing a rash may not be very accurate and necessitates a consultation with a medical professional.