The different types of dermatitis are classified according to the cause of the condition.
Contact dermatitis is the condition caused by an allergen or an irritating substance. Irritant contact dermatitis accounts for 80% of all cases of contact dermatitis.
Atopic dermatitis is very common worldwide and increasing in prevalence. It affects males and females equally and accounts for 10%-20 % of all referrals to dermatologists. More prone to develop this type of dermatitis are individuals who live in urban areas with low humidity.
Dermatitis herpetiformis is a particular type of dermatitis that appears as a result of a gastrointestinal condition, known as celiac disease.
Seborrheic dermatitis is more common in infants and in individuals between 30 and 70 years old. It appears to affect primarily men and it occurs in 85% of people suffering from AIDS.
Nummular dermatitis is a less common type of dermatitis, with no known cause and which tends to appear more frequently in middle-aged people.
Stasis dermatitis is an inflammation on the lower legs which is caused by buildups of blood and fluid and it is more likely to occur in people with varicose.
Perioral dermatitis is somewhat similar to rosacea and it appears more often in women between 20 and 60 years old.
Signs and symptoms
Dermatitis symptoms vary with all different forms of the condition. They range from skin rashes to bumpy rashes or including blisters. Although every type of dermatitis has different symptoms, there are certain signs that are common for all of them, including redness of the skin, swelling, itching and skin lesions and sometimes oozing and scarring. Also, the area of the skin on which the symptoms appear tends to be different with every type of dermatitis.
The symptoms of contact dermatitis usually appear at the site where the allergen got into contact with the skin. Also, the symptoms of neurodermatitis are limited to a single area, often the neck, wrist, forearm, thigh or ankle. More rarely, the primary symptom of this condition which is itchy skin may appear on the genital area, such as the vulva or scrotum.  Symptoms of this type of dermatitis may be very intense and may come and go. Irritant contact dermatitis is usually more painful than itchy.
Although the symptoms of atopic dermatitis vary from person to person, the most common symptoms are dry, itchy, red skin. Typical affected skin areas include the folds of the arms, the back of the knees, wrists, face, and hands. Less commonly there may be cracks behind the ears, and various other rashes on any part of the body.  Itching is the primary symptoms of this condition.
Dermatitis herpetiformis symptoms include itching, stinging and a burning sensation. Papules and vesicles are commonly present. The small red bumps experienced in this type of dermatitis are usually about 1 cm in size, red in color and may be found symmetrically grouped or distributed on the upper or lower back, buttocks, elbows, knees, neck, shoulders, and scalp.  Less frequently, the rash may appear inside the mouth or near the hairline.
The symptoms of seborrheic dermatitis on the other hand, tend to appear gradually, from dry or greasy scaling of the scalp (dandruff) to hair loss. In severe causes, pimples may appear along the hairline, behind the ears, on the eyebrows, on the bridge of the nose, around the nose, on the chest, and on the upper back.  In newborns, the condition causes a thick and yellowish scalp rash, often accompanied by a diaper rash.
Perioral dermatitis causes a red bumpy rash around the mouth.
A number of health conditions, allergies, genetic factors and irritants can be responsible for causing dermatitis. There are several types of dermatitis which are distinguished based on the particular factor that triggers the skin reaction.
Laundry soap, cleaning products, detergents or skin soaps may cause contact dermatitis. This specific type of dermatitis can also be caused by the exposure to allergens such as rubber, metal (nickel), jewelry, cosmetics, fragrances and perfume, weeds (such as poison ivy) or a common ingredient found in topical antibiotic creams which is called neomycin. Individuals develop this condition due to a brief exposure to the allergen or to a prolonged exposure to an irritant, such as those mentioned above. Generally, people who become sensitive to an allergen will be allergic to it for the rest of their lives.
Dry skin, chronic irritation, eczema and psoriasis are possible causes of neurodermatitis.
Another type of dermatitis, seborrheic dermatitis is usually caused by physical stress, neurological conditions such as Parkinson's disease or by travelling. Varicose veins and chronic conditions or infections that affect the blood flow in the legs account for potential causes of stasis dermatitis.
The cause of atopic dermatitis is not known, but the disease seems to result from a combination of genetic (hereditary) and environmental factors. Usually, an irritable skin, a poor immune system and a genetic factor are included among the causes of this condition. Although stress does not cause this type of dermatitis, it has been proven to worsen it. Not least, makeup, moisturizers, topical corticosteroids and dental products that contain fluoride may cause perioral dermatitis.
Dermatitis herpetiformis is one of the other types of dermatitis and it is caused by a gastrointestinal condition called celiac disease. Celiac disease often results after the ingestion of aliments that contain gluten.
Treating dermatitis is made accordingly with the particular cause of the disease. Creams that contain corticosteroids, wet compresses and avoiding the allergens and irritants are part of most treatment plans. For some types of dermatitis, nonsteroidal medications may help relieve signs and symptoms. And for all types of dermatitis, occasional use of over-the-counter antihistamines can reduce itching.