What is eczema of the scalp?
LAST UPDATED: Jan 25, 2021
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Eczema of the scalp is most commonly due to a condition of the skin known as seborrheic dermatitis. This chronic condition causes an itchy rash on certain parts of the body, which goes away and comes back during “flare-ups.” When it is mild, dandruff may be the only sign that you have it. But when it is more severe, this condition can cause redness or irritation, swelling, intense itching, and the development of white or yellow scales on the skin.
These patches of skin will not appear dry; instead, they often appear greasy or moist (Schwartz, 2006). While dandruff affects only the scalp, more severe seborrheic dermatitis can also affect other areas of the body like the face, behind the ears, armpits, and the upper chest (Borda, 2015).
In infants, seborrheic dermatitis goes by the name of cradle cap. Cradle cap causes scaly patches of skin on the baby’s scalp with a crusty appearance—but this condition is harmless. It will often disappear between six months and one year of age (Borda, 2015). Cradle cap and dandruff are quite common amongst children; a study published in 2003 found that greater than 40% of the children surveyed had dandruff (Foley, 2003).
In adults, however, this condition can be more pervasive and long-lasting. The symptoms can come and go for the rest of a person’s adult life and can “flare-up” due to certain risk factors such as stress or exposure to cold or dry air.
Furthermore, seborrheic dermatitis is not contagious, affects males more than females, and is estimated to affect over half of the adult population worldwide—with an increased incidence in people who are HIV positive and in patients living with Parkinson’s disease (Borda, 2015).
What causes seborrheic dermatitis?
While the exact cause of seborrheic dermatitis is not known, several well-documented ideas have been proposed. One school of thought is that the condition is caused by a species of yeast called Malassezia (specifically M. globosa and M. restricta, among others) (Gaitanis, 2012).
This yeast is considered a normal part of what scientists call the “human microbiome,” meaning it is a naturally occurring part of the human skin’s ecosystem. This ecosystem includes several bacteria and fungi that are beneficial and sometimes essential to human survival. But scientists are unsure whether seborrheic dermatitis is caused by having too much of the fungus or by having a reaction to it (Borda, 2015).
Another proposed theory is that seborrheic dermatitis is caused by an excess production of an oily fluid called sebum. Sebum is a greasy fluid secreted in response to hormones that protects the skin against friction and lubricates it, locking in moisture. Sebaceous glands (which are responsible for producing sebum) are found inside the skin on virtually the entire body’s surface except on the palms of your hands and the soles of your feet (Makrantonaki, 2011).
Scientists concluded that sebum production is related to seborrheic dermatitis because this disease occurs more commonly during the parts of life where your body produces the most sebum. However, some patients with seborrheic dermatitis have typical amounts of sebum, and not all adults with excess sebum go on to develop the disease (Borda, 2015).
Several individual factors also play a role in the development of seborrheic dermatitis, including but not limited to genetics, your immune system, the makeup of the outermost layer of your skin (known as the epidermis), stress, and nutrition (Borda, 2015).
What is the difference between seborrheic dermatitis and psoriasis?
Psoriasis is a chronic but less common condition that also can cause irritation on the scalp. It only affects about two percent of adults in the United States. Just like seborrheic dermatitis, psoriasis can cause an intense itch and inflammation. In fact, some of the symptoms of psoriasis can be the same as those of seborrheic dermatitis. Symptoms of psoriasis include:
Red patches (‘plaques’) on the scalp
Dry, itchy scalp
A sensation of burning or soreness
Temporary hair loss
These symptoms are also similar in that they can come and go, flaring up due to stress or exposure to cold, dry air. But psoriasis is a distinct condition with its own risks and treatments. For example, injury to the skin is a common risk factor for triggering psoriasis and not seborrheic dermatitis. Another visible difference between the two is that the parts of the scalp affected by psoriasis are not only inflamed and itchy, they also have a silvery scale-like appearance (Weigle, 2013).
Talk to your healthcare provider or a dermatologist if you are having trouble determining which condition you might have. While these conditions may appear similar, they require different medications for treatment.
What else can cause scalp eczema?
There are a few other conditions that can cause eczema of the scalp:
Atopic dermatitis is the most common form of eczema when not specifically talking about the scalp, but it can affect the scalp as well. The most significant risk factor for atopic dermatitis is a family history, and this condition has many environmental triggers (like pollen or mold), which can make symptoms worse (Eichenfield, 2014).
Contact dermatitis comes in two flavors: allergic contact dermatitis and irritant contact dermatitis. It appears as a rash on your skin after coming into contact with an irritating substance or a substance to which you’ve developed an allergy (Usatine, 2010).
Neurodermatitis is a condition that occurs more often in women between the ages of 30–50 and can cause itchy, raised patches on the skin (An, 2013).
Treatments for these conditions range from simple lifestyle changes to prescription creams that work with your body’s immune system to help control your symptoms. To learn more about the other types of eczema and their treatments, click here.
What are some of the treatment options available for seborrheic dermatitis?
There are multiple over-the-counter options available for the treatment of scalp eczema, including (Borda, 2015):
Zinc pyrithione shampoos (brand names DermaZinc and Head & Shoulders) contain an antifungal agent with demonstrated activity against Malassezia species.
Tar-based shampoos slow down the flaking associated with dandruff.
Salicylic acid-containing shampoos can reduce inflammation and scaling caused by the condition.
Selenium sulfide shampoos (brand name Selsun Blue) contain a different antifungal agent that fights against the fungus associated with seborrheic dermatitis.
Ketoconazole shampoos (brand name Nizoral A-D) also contain an antifungal medication.
It is critical to use all of these products as instructed on the product label. Some products are used daily, while others might only be used once a week. You’ll also want to rinse them out well after use because several can cause discoloration if they stay on your scalp for too long. If one type of shampoo seems to lose its effectiveness over time, you can try a second type and alternate between the two to control your dandruff.
Suppose over-the-counter options fail to help with your dandruff. In that case, some prescription-strength shampoos and foams contain a higher medication concentration and may be more effective. The most commonly prescribed medications contain ketoconazole or salicylic acid and should only be used under a healthcare provider’s supervision.
Other prescription options for seborrheic dermatitis include topical steroids, antibiotics, topical calcineurin inhibitors (such as pimecrolimus), and antifungal medications (Borda, 2015).
Scalp eczema can be an irritating, lifelong symptom that can cause many people to have anxiety and stress. Still, it is important to keep in mind that there are options available to control it. Talk to your healthcare provider about treatment options and for advice on how to manage relapses.
If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
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