What is Seborrheic Dermatitis?

The cause, triggers and complications of the dermatitis of the sebaceous areas

Seborrheic dermatitis, the dermatitis of the sebaceous areas, is a common disease. It may be considered part of a clinical spectrum which include dandruff and psoriasis..

The Clinical Spectrum of Seborrheic Dermatitis

Seborrheic dermatitis is a common skin disease associated with increased and altered sebum production and yeast colonization.  Seborrheic dermatitis presents as a chronic dermatitis in sebum rich areas of the body like scalp, face and upper trunk. Its milder, non-inflammatory form is known as dandruff.  Seborrheic Dermatitis affects 1-3% general population, though dandruff is a very common occurrence. More than 36% of HIV positive patients have Seborrheic Dermatitis.

What is the cause for Seborrheic Dermatitis?

Seborrheic dermatitis appears in genetically pre-disposed individuals with the so called seborrheic diathesis, meaning increased sebum secretion  in the sebaceous gland rich areas of the body-  the scalp, face, front of chest, and in between the shoulder blades.  Certain triggering agents plus the greasiness of the skin in these areas is a flourishing ground for the yeasts known as malassezia. These yeasts breakdown and alter the composition of the sebum which further sets in motion an inflammatory response in the skin. This again increases the sebum secretion and the cycle continues.

Seborrheic dermatitis in the nasal fold.
Seborrheic dermatitis in the nasal fold.

The skin becomes red, irritated and scaly. Itching is prominent in acute, active state. In addition to the classical sites, seborrheic dermatitis can also affect the eyelids, armpits, groin and gluteal fold.

Seborrheic Dermatitis can cause an intensely itchy scalp.
Seborrheic dermatitis is a cause for severe itchy scalp.

Malassezia species M.restricta and M.globosa have been isolated from the seborrheic dermatitis skin.

Seborrheic dermatitis is seen in the first  few months of life when maternal androgens are present in the blood. Then, the disease re appears in susceptible individuals after the sebaceous glands become active during puberty.

Seborrheic dermatitis can be considered a part of the clinical spectrum between dandruff and psoriasis. (See the Figure above)

What are the triggers for Seborrheic Dermatitis?

  1. Stress & Fatigue. Both lowered immunity and hormonal stimulation are the reasons for increased seborrheic dermatitis in stressed and fatigued conditions.
  2. Hormonal  Triggers . Androgen hormones control the sebaceous activity in humans. Probably these are under the control of a sebotrophic hormone secreted from the hypothalamus. Body builders using anabolic steroids get severe attacks of seborrheic dermatitis.
  3. Environmental Triggers. Seborrheic dermatitis is precipitated in low humid conditions and in winter.
  4. Low Immune states. Either due to medications, or diseases like HIV and malignancies trigger seborrheic dermatitis.
  5. Food. Sugar consumption, fast foods, Vit B including B12 malutilization, biotin deficiency, niacin deficiency, pyridoxine deficiency, zinc deficiency and excess alcohol consumption have all been found to increase the incidence of seborrheic dermatitis .
  6. Drugs. Broad spectrum Antibiotics, OCP, Systemic Steroids, buspirone, chlorpromazine, cimetidine, ethionamide, griseofulvin, haloperidol, interferon alfa, lithium, methoxsalen, methyldopa, phenothiazines, psoralens, stanozolol are some of the medications that have been found to increase seborrheic dermatitis. The list is not complete.
  7. Diseases. Seborrheic dermatitis may be the presenting feature of Parkinsonism and  HIV infection. Incidence of seborrheic dermatitis is high in epilepsy, idiopathic post encephalitis,  diabetes mellitus, paralytic states etc.

What are the other causes for Itchy Scalp?

Seborrheic dermatitis has to be differentiated from other causes of itchy scalp, like scalp  dryness, contact allergy and psoriasis, all of which cause itchy and scaly scalp. For details see Causes of Itchy Scalp.

What are the types of Seborrheic Dermatitis?

  1. Infantile Seborrheic Dermatitis
    1. Cradle cap
    2. Trunk: Flexural, napkin area
    3. Leiner’s disease
  2. Adult Seborrheic Dermatitis
    1. Scalp: Dandruff and inflammatory types.
    2. Face: Inflammatory and non inflammatory, with blepharitis(eye lid)
    3. Trunk: Petaloid, pityriasiform, follicular, follicular, eczematous type
    4. Generalized exfoliative erythroderma
Seborrheic Dermatitis Chest. Image Courtesy: Galderma
Seborrheic Dermatitis Chest

What are the complications of Seborrheic Dermatitis?

  • Psychosocial impact: Chronic visible disease may affect a person’s self esteem.
  • Secondary bacterial infection with Staphylococcus aureus may occur, with typical impetigo with increased redness, oozing, and crusting.

What is Leiner’s Disease?

Leiner’s disease is a complication of seborrheic dermatitis in infants with C5 complement deficiency. There is usually a sudden confluence of lesions leading to a generalised scaling and redness of the skin. The child is severely ill with anemia, diarrhea, and vomiting. Secondary bacterial infection is common.

Because of the varied internal causes, it is quite difficult to get rid of seborrheic dermatitis. But, with some life style changes and appropriate treatment,  it is possible to get rid of Seborrheic Dermatitis.

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Disclaimer

The information given in this article is for educational purpose only so that patients are aware of the options available for diagnosis and treatment of common skin, hair and nail diseases. No diagnosis should be made or treatment undertaken without first consulting your dermatologist. If you do so, the author will not be responsible for any consequences. The images provided are for illustration purpose only and should not be reproduced without the consent of the author.

About the Author of Skin Care Tips from Dermatologist: Dr Hanish Babu, MD
Dr Hanish Babu, MD, Dermatologist, Sharjah and Ajman, UAE
Dr Hanish Babu, MD

Dr Hanish Babu, MD is a dermatologist with more than 3 decades of experience in treating skin and sexually transmitted diseases in UAE and India. He has been practicing in UAE since last 22 years. He is a respected speaker during the Continuing Medical education Programmes for doctors, medical students and paramedical staff and is also a Stress Management Trainer. He organises group therapy sessions for patients with psoriasis, eczema and vitiligo.

He is available for consultation at Cosmolaser Medical Centre in Samnan, Sharjah (06 5678 200) from 9 am – 1 pm and at City Medical Centre, Al Bustan, Ajman (06-7 441 882) from 4.30 pm – 9.30 pm.

Visit his personal website  dr-hanishbabu.com for more details and for educational articles on Skin, hair, nail and sexually transmitted diseases. Click here to Book an Appointment with dermatologist Dr Hanish Babu, MD

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