There are a wide variety of causes for rashes and irritated skin, yet treatment can vary widely. Appropriate care for one type of skin irritation can actually worsen irritation from other source. A dermatologist can use subtle differences in the appearance of irritated skin, along with specific tests, to determine the cause and suggest an appropriate course of action to alleviate the irritation.
Dry skin can occur at any age and for many reasons. In general, skin becomes drier with age, during the winter months, and in low-humidity climates, such as Montana.
Allergic contact dermatitis
Allergic contact dermatitis is caused by a reaction to substances called allergens that come into contact with your skin. In susceptible people, these contact allergens can cause itching, redness, and blisters that is known as allergic contact dermatitis. In initial (acute) severe cases such as poison ivy, the skin gets red, itchy, swollen, and develops tiny blisters, which may break and leave crusts and scales. The skin becomes thick, red, and scaly with long-term (chronic) exposure to an allergen. Later the skin may darken and become leathery and cracked. Allergic contact dermatitis can be difficult to distinguish from other rashes. A dermatologist will study the materials that your skin encounters at work and at play to try to identify the allergen. Most contact dermatitis is diagnosed by distribution of the rash. Sometimes the cause cannot be identified by history or physical examination and your dermatologist may want to perform patch tests.
Allergic Contact Rash
Patch tests are a safe and easy way to diagnose contact allergies. Patch tests are different from injection or scratch skin tests because they test for different allergens. In patch tests, small amounts of the possible common allergens are applied to the skin on strips of tape and then removed after two days. A positive allergy test shows up as a small red spot at the site of the patch. Common allergens include nickel, rubber, dyes, preservatives, medications, fragrances, poison ivy, poison oak, and related plants.
Fungal Infections of the Skin
Having a fungal infection of the skin or nails, also called tinea, is quite common. Fungal infections are contagious. Sometimes people get a fungal infection from direct contact with an infected person. A fungal infection also can be picked up by touching an infected pet or item contaminated with the fungus. Fungi thrive in warm, moist areas. A comb, clothing, shower surface, or pool area can harbor tinea. For most people, a fungal infection is generally mild. If a person has a medical condition that suppresses the immune system such as HIV, AIDS, or cancer, a fungal infection can be serious. Common fungal infections include athlete's foot, ringworm, jock itch, and nail fungus.
An inherited skin condition, keratosis pilaris, occurs in up to 40% of the population. It is commonly seen in children and young adults; the condition may continue later in life. Characterized by tiny, flesh-colored to slightly red bumps that give the skin a sandpaper-like texture, keratosis pilaris develops on the outer areas of the upper arms. It also frequently occurs on the thighs and cheeks. Each tiny bump is a plug of dead skin cells that forms at the site of a hair follicle. Keratosis pilaris occasionally itches, especially during the winter months and in low-humidity climates. When humidity increases during the summer it leaves skin less dry, and the red coloration becomes somewhat camouflaged. Since keratosis pilaris is a benign condition, people usually seek treatment due to the itch or for cosmetic reasons. Moisturizers may help with the dryness and associated itch. Urea preparations and lactic acid creams are often effective moisturizers; however, moisturizers do not tend to clear the bumps. Mild peeling agents are most effective in opening the plugged hair follicles and work by removing the excess skin. Topical retinoids also are commonly used to treat keratosis pilaris.
Hives are localized, pale, itchy, pink wheals (swellings) that can burn or sting. They may occur singularly or in groups on any part of the skin; they are part of an allergic reaction and are very common. Approximately 10-20 percent of the population will have at least one episode in their lifetime. Most episodes of hives disappear quickly in a few days to a few weeks. Occasionally, a person will have them for many months or years. New hives may develop as old ones fade. Hives can vary in size from as small as a pencil eraser to as large as a dinner plate, and may join to form even larger swellings. Hives are produced by blood plasma leaking through tiny gaps between the cells lining small blood vessels in the skin. Histamine is a chemical released from cells in the skin called "mast cells" which lie along blood vessels. Allergic reactions, chemicals in foods, or medications may cause hives; sometimes it is impossible to find out the cause. When hives form around the eyes, lips, or genitals, the tissue may swell excessively. Although frightening, the swelling usually goes away in less than 24 hours. Severe cases of hives may cause difficulty in breathing or swallowing and emergency room care is required.