SKINIPEDIA - Skin Encyclopedia: Dermatitis
Dermatitis
The term dermatitis refers to any inflammation (swelling, itching, and redness) possibly associated with the skin. There are many types of dermatitis, including:
- Atopic dermatitis (eczema). It's a common, hereditary dermatitis that causes an itchy rash primarily on the face, trunk, arms, and legs. It commonly develops in infancy, but can also appear in early childhood. It may be associated with allergic diseases such as asthma and seasonal, environmental, and food allergies.
- Contact dermatitis. This occurs when the skin comes into contact with an irritating substance or one that the person is allergic or sensitive to. The best-known cause of contact dermatitis is poison ivy, but there are many others, including chemicals found in laundry detergent, cosmetics, and perfumes, and metals like nickel plating on jewelry, belt buckles, and the back of a snap.
- Seborrheic dermatitis. This oily rash, which appears on the scalp, face, chest, and back, is related to an overproduction of sebum from the sebaceous glands. This condition is common in infants and adolescents.
Bacterial Skin Infections
- Impetigo. Impetigo is a bacterial infection that results in a honey-colored, crusty rash, often on the face near the mouth and nose.
- Cellulitis. Cellulitis is an infection of the skin and subcutaneous tissue that typically occurs when bacteria are introduced through a puncture, bite, or other break in the skin. The area with cellulitis is usually warm, tender, and has some redness.
- Streptococcal and staphylococcal infections. These two kinds of bacteria are the main causes of cellulitis and impetigo. Certain types of these bacteria are also responsible for distinctive rashes on the skin, including the rashes associated with scarlet fever and toxic shock syndrome.
Fungal Infections of the Skin and Nails
- Candidal dermatitis. A warm, moist environment, such as that found in the folds of the skin in the diaper area of infants, is perfect for growth of the yeast Candida. Yeast infections of the skin in older children, teens, and adults are less common.
- Tinea infection (ringworm). Ringworm, which isn't a worm at all, is a fungus infection that can affect the skin, nails, or scalp. Tinea fungi can infect the skin and related tissues of the body. The medical name for ringworm of the scalp is tinea capitis; ringworm of the body is called tinea corporis; and ringworm of the nails is called tinea unguium. With tinea corporis, the fungi can cause scaly, ring-like lesions anywhere on the body.
- Tinea pedis (athlete's foot). This infection of the feet is caused by the same types of fungi that cause ringworm. Athlete's foot is commonly found in adolescents and is more likely to occur during warm weather.
Other Skin Problems
- Parasitic infestations. Parasites (usually tiny insects or worms) can feed on or burrow into the skin, often resulting in an itchy rash. Scabies and lice are examples of parasitic infestations. Both are contagious and can be easily caught from other people.
- Viral infections. Many viruses cause characteristic rashes on the skin, including varicella, the virus that causes chickenpox and shingles; herpes simplex, which causes cold sores; human papillomavirus, the virus that causes warts; and a host of others.
- Acne (acne vulgaris). Acne is most common in teens. Some degree of acne is seen in 85% of adolescents, and nearly all teens have the occasional pimple, blackhead, or whitehead.
- Skin cancer. Skin cancer is rare in children and teens, but good sun protection habits established during these years can help prevent skin cancers such as melanoma (a serious form of skin cancer that can spread to other parts of the body) later in life, especially among fair-skinned people who sunburn easily.
In addition to these diseases and conditions, the skin can be injured in a number of ways. Minor scrapes, cuts, and bruises heal quickly on their own, but other injuries — severe cuts and burns, for example — require medical treatment.
Disorders of the Scalp and Hair
- Tinea capitis, a type of ringworm, is a fungal infection that forms a scaly, ring-like lesion in the scalp. It's contagious and common among school-age children.
- Alopecia is an area of hair loss. Ringworm is a common cause of temporary alopecia in children. Alopecia can also be caused by tight braiding that pulls on the hair roots (called tension alopecia). Alopecia areata (when hair falls out in round or oval patches on the scalp) is a less common condition that can affect children and teens.