Eczema and seborrhea are some of the most common inflammatory skin conditions.

What is eczema?

According to the American Academy of Dermatology, one of the most common forms of eczema is atopic dermatitis. If you have it, your skin has ongoing dry, red, extremely itchy patches. They can show up on just about any part of your body, but typically appear on your forehead, cheeks, forearms, legs, scalp and neck.

"There are about 10 forms of eczema, each with their own presentations and diagnoses," says Dr. Erik Simpson, director of dermatology clinical studies at Oregon Health & Science University in Portland, Oregon. "[M]ost people refer to eczema and use the term synonymously with the term atopic dermatitis, which is a childhood inflammatory skin disorder that affects 10 percent of the population of schoolchildren in the United States."

The main symptom of eczema is itching. The good news is most people who have eczema have only a mild form of it. It can, however, be hard on kids and their families. "You run into problems with social stigma as well as the symptoms of itch interfering with sleep and concentration," says Dr. Simpson. "It's mainly seen in children, but a small percentage of people will continue to have this into adulthood, such as hand eczema."

There's no known cause for the disease, and the National Institutes of Health think that 15 million people in the U.S. have some form of eczema. You can often keep yourself from having an eczema outbreak by frequently moisturizing, avoiding hot or humid conditions and sudden changes in temperature or humidity, reducing stress, avoiding rough fabrics like wool, and steering clear of things in the environment that trigger allergies.

Eczema treatment

Since eczema is dry and itchy, not scratching (which sounds easier than it is) is key. Treatment options include:

  • Corticosteroids: These drugs, often in creams or lotions, help reduce inflammation.
  • Over-the-counter antihistamines: These medications, which include Benadryl, Dimetapp, Alavert and Claritin, can help reduce the inflammation and itch.
  • Coal tar treatments: Tar and extracts of crude coal tar are often used to reduce the amount of steroid creams or lotion you might need to use to keep ongoing eczema under control. Tar products are available in shampoo form (T/Gel, Neutrogena, Denorex), creams and oils. They have long been used for mild cases of atopic dermatitis. Unfortunately, tar smells like, well, tar and tends to irritate dry skin.
  • Phototherapy: Phototherapy uses ultraviolet light from special lamps (under professional supervision) at least three times a week. It's used for people with severe eczema.

Just remember that not every treatment is right for everyone, so check with your doctor to see what might work best for you.

And rest assured, according to Dr. Simpson, new treatments are on the horizon. "The most interesting thing is that this does not appear to be an allergic disease, but appears to be a disease where the underlying defect is in the skin barrier," he says. "There's been a gene found called filaggrin that is the strongest predisposing factor in determining whether someone is going to get eczema or not. Your skin is a barrier from … micro-irritants—and if that's genetically impaired, you're more susceptible to [them]."

Based on the new research, it's likely that this genetic defect causes inflammation throughout your body. That inflammation makes is more likely you'll be affected by allergies. "The confusion lies in the fact that patients with eczema get allergies," says Dr. Simpson. "They get food allergies, hay fever, asthma, and so we used to think that eczema was caused by allergy … [so] this is a paradigm shift in this disease."

That change in the way doctors think about the condition has opened up new ways to look at prevention and treatment. "New treatments are coming out focusing on the skin barrier for prevention of eczema," says Dr. Simpson. "Potentially, in the future, it may be that improving the skin barrier can reduce the amount of allergy that's involved that develops subsequently to the eczema. And that opens up options for new therapies that may have some implications for the development of allergic disease, as well."

What is seborrhea?

There's been little new information in recent years about seborrhea, or seborrheic dermatitis. Seborrhea is an ongoing inflammatory skin disorder. If you have it, you have red or flaking skin around your nose, eyebrows and scalp.

"Seborrheic dermatitis is dandruff, but we still don't know what causes it," says Dr. Simpson. "It's technically an eczema, but it's less itchy, more greasy and scaly. … [But] under the microscope it looks the same."

Seborrhea treatment

According to Dr. Simpson, "Typical treatments are dandruff shampoos that kill yeast and topical [steroidal] anti-inflammatories like cortisones … nonsteroidal anti-inflammatories are the only thing new in treatment for seborrhea."

Most dandruff shampoos are antifungal shampoos that you can buy without a prescription. They usually have selenium sulfide, pyrithione zinc, sebulon or ketoconazole in them.

Steroids reduce the inflammatory response and can help control itching. Steroid creams and lotions can reduce the redness and itching of seborrheic dermatitis. Hydrocortisone cream can be used for flare-ups, and antifungal shampoo can keep the seborrhea under day-to-day control.

If applying moisturizers for eczema or keeping a clean scalp for seborrheic dermatitis doesn't help, talk to your doctor about other options.

Published on July 15, 2009; updated on June 6, 2014.