Dry, flaky skin on your scalp can be uncomfortable and embarrassing. Those flakes can be caused by dandruff or psoriasis, which are two very different conditions.
Dandruff, known as seborrhea, can usually be treated relatively easily and is seldom a serious medical problem. Psoriasis, on the other hand, is a chronic condition without a current cure, and one that can cause a great deal of pain and discomfort.
How dandruff develops
Dandruff is a condition marked by flakes of dry skin on the scalp. The flakes can often fall from your hair and land on your shoulders. Dandruff usually results from a dry scalp. If this is the cause, the flakes are typically small and you may have dry skin on other parts of your body.
Washing your hair with a harsh shampoo or using a lot of chemicals on your hair can sometimes irritate your scalp and lead to flakes.
A fairly common condition called seborrheic dermatitis is the cause of many dandruff cases. It’s characterized by patches of red and oily skin that leave yellowish flakes on the scalp. These flakes are often larger than dandruff flakes that occur from dry skin. Seborrheic dermatitis can also cause flaky, irritated patches elsewhere on your body, which may lead you to think you have psoriasis.
How psoriasis develops
Unlike dandruff, psoriasis is a problem rooted in your immune system. It’s considered an autoimmune disease, which means special proteins called autoantibodies attack healthy tissue.
Regular antibodies only appear to fight off an infection caused by a virus or bacteria. If you have psoriasis, your immune system causes an unhealthy and abnormal growth of new skin that collects in dry, flaky patches on your body, including the scalp.
Normally, dead skin is shed in tiny, thin fragments from the outermost layer of skin. Neither you nor anyone else can ever tell that you’re losing dead skin. New, healthy skin cells are forming beneath the surface of your skin and in a matter of weeks rise to the surface to replace the dead skin.
If you have psoriasis, that process speeds up in various spots on your body, so there’s no time for the dead skin to go through its normal shedding. That causes dead skin cells to build up on the surface. This usually occurs on the:
Psoriasis can take different forms. Sometimes your skin may look cracked and dry. Other times it may be reddened and dotted with small silvery patches.
There’s no way to prevent psoriasis. It can develop in anyone at any age, but is less common in children. It usually first appears in adults between the ages of 30 and 39 or between the ages of 50 and 69.
Dandruff, however, can usually be prevented. Using a daily dandruff shampoo is often enough to keep dandruff from forming. Keeping your hair clean, in general, is a good idea. Oil and dirt can build up on your scalp and cause your scalp to dry. Brushing your hair away from the scalp will also help keep oil from accumulating on your scalp.
Psoriasis can be treated with topical lotions and medications, many of which are steroids, but those only serve to make the symptoms somewhat milder. There’s no cure. Drugs known as disease-modifying antirheumatic drugs are given to people with moderate to severe psoriasis. Light therapy, which targets psoriasis trouble spots with specially directed ultraviolet light, can also help treat the symptoms of psoriasis.
Dandruff, on the other hand, can usually be treated with medicated shampoo. It’s also important that you follow the directions of any shampoo you use. Some can be used a couple of times per week, and others should only be used once per week. You may have to switch shampoos, too, as one may become less effective over time.
When to see a doctor
If your dandruff doesn’t go away, or get better after two weeks of antidandruff shampoo, you may need to see a dermatologist. There are prescription dandruff shampoos that may have the strength you need to overcome the problem. You may also require a medicated ointment.
If all signs point to psoriasis, you should also see a dermatologist. You may have psoriatic arthritis if stiff or swollen joints accompany your psoriasis. A rheumatologist can treat this condition. Your primary care physician should be able to help coordinate your care and your various specialists.