Rashes are minor irregularities on the skin that appear in the form of bumps or sores, a scaly texture or redness. The cause can range from genetic to environmental factors. Here are some of the common causes of skin rashes.

• Contact dermatitis:  Contact dermatitis is a type of rash that occurs due to direct contact with any substance. Irritant dermatitis occurs when acidic or alkaline substances such as soap and detergents come into skin contact resulting in a burn-like reaction.

If your skin comes in contact with substances to which you are allergic, then it results in allergic contact dermatitis. Examples include substances such as adhesives, latex or perfumes.

Seborrheic dermatitis:  Seborrheic dermatitis is the scientific name of the commonly occurring scalp issue dandruff. It is a skin rash that appears as red and scaly patches. It can occur due to over shampooing, frequent combing, use of certain cosmetic products, use of alcohol-based lotions, irritation from a fungus called Malassezia, dry skin or build-up of oil and dirt on the scalp, stress, fatigue, lack of zinc or B-vitamins, a weak immune system, or nervous system problems.

Atopic dermatitis:  A chronic condition, it causes itchy or inflamed skin. It increases the permeability of the skin resulting in the reduction of its antimicrobial function. The loss of the skin barrier can allow the irritants such as soaps and dirt to penetrate the skin.

Other conditions
Additionally, there are some other causes of skin rashes. For instance, psoriasis is an inherited, autoimmune disease that causes a rash resembling red, scaly, itchy patches over joints and along the scalp. Impetigo occurs because of a certain type of bacteria. The resulting rashes are red sores that turn into blisters, ooze, and then crust over. Shingles or herpes zoster is a painful, blistering skin rash. Measles, rubella and scarlet fever also manifest in the form of rashes.

• Autoimmune disorders:  Certain autoimmune diseases such as erythematosus, juvenile rheumatoid arthritis, and Kawasaki disease might cause skin rashes.
• Pregnancy:  The most common pregnancy-specific skin rashes are pruritic urticarial papules and plaques of pregnancy (PUPPP).
• Medications:  Some of the most common reasons for the rashes due to drugs are an allergic reaction to drugs or hypersensitivities to certain medications.
• Insect bites:  Insect bites and stings can also cause skin rashes, but these do not last long.