What is dermatitis?
Dermatitis is inflammation of the skin. Depending on the type of dermatitis, areas of skin may become red and itchy with some acute attacks causing crusty scales or blisters that ooze fluid.
Types of dermatitis
- Contact dermatitis - Contact dermatitis typically causes the skin to develop a pink or red rash, which usually itches. Pinpointing the exact cause of contact dermatitis can be difficult. Contact dermatitis may be irritant or allergic. Common chemical irritants include detergents, soaps, some synthetic fibres, nail polish remover, anti-perspirants, and formaldehyde (found in non-iron fabrics, polishes, artificial-fingernail adhesive, chipboard, and foam insulation). Some plants, in particular primula, chrysanthemums, daffodils and tulips, irritate some people. Wearing rubber gloves, or nickel or cobalt in jewellery can cause contact allergic dermatitis if the person is allergic to these substances. Both types of contact dermatitis may be caused by cosmetics, perfumes, hair dyes, and skin-care products.
- Nummular dermatitis - Nummular dermatitis consists of distinctive coin-shaped red plaques that are most commonly seen on the legs, hands, arms, and torso. It is more common in men than women and the peak age of onset is between 55 and 65. Living in a dry environment or having very hot showers can cause this condition.
- Atopic dermatitis (eczema) - Atopic dermatitis causes the skin to itch, scale, swell, and sometimes blister. This type of eczema usually runs in families and is often associated with allergies, asthma, and stress.
- Seborrhoeic dermatitis - Seborrhoeic dermatitis consists of greasy, yellowish, or reddish scaling on the scalp and other hairy areas, as well as on the face or genitals, and in skin creases along the nose, under the breasts, and elsewhere. This condition is called cradle cap in infants and is likely to be related to maternal hormonal changes affecting the sebaceous glands (glands that produce a natural greasy substance, sebum). It may be aggravated by stress.
- Stasis dermatitis - Stasis dermatitis is caused by poor circulation and can happen in people with varicose veins, congestive heart failure, or other conditions. Veins in the lower legs fail to return blood efficiently, causing pooling of blood and fluid build-up and oedema. This leads to irritation, especially round the ankles.
What are the symptoms of dermatitis?
Dry, reddish, itchy skin indicates some kind of dermatitis, or skin inflammation, of which there are many types:
- A red rash that is limited to the area of skin exposed to an irritant is probably contact dermatitis.
- Red, itchy, circular patches of weeping, scaly, or encrusted skin suggest nummular dermatitis, common in older people who have dry skin or live in dry environments.
- Greasy, yellowish scales on the scalp and eyebrows, behind the ears, and around the nose indicate seborrhoeic dermatitis; in infants it is called cradle cap.
- Scaling, sometimes ulcerated skin appearing inside the lower legs and around the ankles, may indicate stasis dermatitis.
- Extreme, persistent itchiness may signal atopic dermatitis (atopic eczema). Very often, however, itchiness results simply from dry skin.