Skin rashes may appear anywhere on your body or all over your body, and they can have many causes. While rashes are usually simply bothersome and not dangerous, some rashes can be signs of a serious condition that involves other organs of your body. Any rash that doesn't clear up within a reasonable amount of time or that reoccurs should be checked by a doctor to determine its cause.
A hereditary rash is one that was passed down from your parents or grandparents in your genes. Two examples of hereditary conditions are eczema and psoriasis. Eczema involves scaly patches on your arms, legs, scalp and torso. It can be inflamed and very itchy. Psoriasis causes raised red areas and silvery white scales on your elbows, knees, scalp and lower back.
Substances that can induce allergic reactions and cause rashes include poison ivy and oak, perfumes, jewelry the contains nickel, detergents and medications. Allergic reactions are characterized by an itchy red rash, sometimes along with blisters, and are located wherever your skin came in contact with the allergen. In some cases these rashes can spread, such as those from poison ivy and oak.
Fungal and bacterial infections can cause itchy rashes. Two examples of fungal infections are ringworm and yeast infection. Ringworm usually appears in the folds of your skin, such as beneath your breasts or in the groin area. Yeast infection is also known as jock itch in men. Impetigo is a bacterial infection from strep or staph germs and is usually found around the nose and mouth, forearms and hands. It is characterized by large blisters and/or crusty patches.
Viral rashes include infections of the skin, like measles, chickenpox, herpes and shingles. Rather than being in one place, these rashes are usually everywhere. There is no treatment for the actual virus itself, but topical medications are used to treat itchy red rashes. Though there are no cures, there are vaccines for some viruses that cause rashes. Anti-viral medication may help to suppress and reduce herpes outbreaks.
Rashes from insect bites can result from bed bugs, mosquitoes, fleas, chiggers and ticks. Your skin may be inflamed, irritated and itchy. Most are not serious and should eventually go away. However, a rash that develops into a bulls-eye shape could be a sign of Lyme disease, and you should seek medical care. Scabies is an example of a parasite rash. It is characterized by itchy pimply bumps and possibly small blisters. Topical treatments are available to treat scabies.