Seborrheic Dermatitis – A Type Of Dandruff

Often people make mistakes while recognizing dandruff and Seborrheic dermatitis. Both these conditions lead to scales and flakes on the scalp, their causes are the same, and so are their symptoms. But then, why do both conditions have different names?

Let’s understand Seborrheic dermatitis in detail along with the difference between Seborrheic dermatitis and dandruff.

What is Seborrheic dermatitis?

Sebaceous glands are referred to as “seborrheic” while “derm” refers to the skin. When it affects a baby’s scalp, it is known as “cradle cap,” and when it affects a teenager or adult, it is known as “dandruff” (pityriasis capitis).

Seborrheic dermatitis is a common, non-contagious, and easily treated skin condition. This type of dermatitis causes itchy red patches on your skin as well as greasy scales and white or yellow crusty or powdery flakes on your scalp.

Seborrheic dermatitis can manifest itself in other parts of your body. The upper back and chest, face/forehead, creases at the base of your nose, behind your ears, navel (belly button), eyebrows, under your breasts, and creases/bends of your arms, legs, and groin are the areas with the most sebaceous (oil) gland activity.

What is the difference between Seborrheic dermatitis and dandruff?

Dandruff and Seborrheic Dermatitis (SD) are two different diseases that both affect the seborrheic areas of the body. Dandruff only affects the scalp and is characterized by itchy, flaky skin that is not visibly inflamed. Along with other seborrheic areas, the scalp may also be affected by SD, which is characterized by itchy, flaky, or scaling skin, inflammation, and pruritus. 

The pathogenesis of SD and dandruff is influenced by a number of intrinsic and environmental factors, including sebaceous secretions, skin surface fungal colonization, individual susceptibility, and interactions between these factors.

Causes of Seborrheic Dermatitis

Several lines of evidence point to yeasts of the genus Malassezia playing a pathogenic role in SD and dandruff. Lipase activity in Malassezia was discovered, which hydrolyzes human sebum triglycerides and releases unsaturated fatty acids such as oleic and arachidonic acid. 

These metabolites cause abnormal keratinocyte differentiation, which results in stratum corneum abnormalities like parakeratosis, intracellular lipid droplets, and irregular corneocyte envelope. Such changes disrupt the epidermal barrier function and initiate an inflammatory response, with or without visible local inflammation.

Other causes of Seborrheic dermatitis are

1. You are more likely to develop this type of dermatitis if you were born with naturally oily skin. 
2. A family history of psoriasis makes you vulnerable as well. 
3. If you live in a dry, cold climate, the weather does not cause seborrheic dermatitis, but it does aggravate it.
4. If you have health issues like immunosuppression, psychiatric disorders, neurological disorders, congenital disorders, etc. you are most prone to SD.

Symptoms of Seborrheic Dermatitis

Some of the SD symptoms can be noted as

1. Itchy white skin flakes on your scalp (dandruff). When scratched, the flakes fall to the ground, mix with your hair, or land on your neck and shoulders.
2. Your skin has red scales.
3. Infants’ heads have crusty yellow scales (cradle cap). A cradle cap should not itch, but scratching the area may cause additional inflammation and break the skin, resulting in bleeding or mild infections.
4. Blepharitis (inflammation of eyelids)
5. Ring-shaped rash which is also known as petaloid seborrheic dermatitis.
6. Flaky patches on your chest and hairline that look like flower petals or rings.
7. Redness in your genital folds and creases, armpits, and beneath your breasts.
8. Hair follicles on your cheeks that are inflamed

Why does Seborrheic dermatitis aggravate?

Reasons, why SD aggravates, are-

• Malassezia is one of the main reasons why SD aggravates. Due to the excessively oily nature of the skin in most individuals, Malassezia fungus tends to over-colonize and aggravate SD.
• An increase in the level of androgens
• An inflammatory reaction
• Other causes are- stress, cold/dry climate, oily skin, hereditary, etc.

Is it Seborrheic Dermatitis or Dandruff?

Dandruff is characterized by white or yellow flakes of dry skin on the scalp. Flaky skin is another symptom of seborrheic dermatitis. Furthermore, this condition can cause skin scaling, itching, redness, swelling, and inflammation. 

Dandruff is always limited to the scalp, whereas seborrheic dermatitis can spread to other seborrheic areas such as the face, ears, and upper chest.

Seborrheic dermatitis commonly affects the scalp, face, upper chest, underarms, and inguinal folds, or groin folds, in adolescents. It affects men more than women. Dandruff is also more common and affects men more than women. Dandruff typically appears during puberty, peaks around the age of 20, and becomes less common after the age of 50.

Bottom Line

There is a thin line between SD and dandruff that can be recognized by the affected areas. Both these conditions are treatable and can be cured with help of anti-inflammatory medications, coal tar shampoo, and intake of immunomodulators.
If you want to know about natural ways of treating seborrheic dermatitis, click here.