Seborrheic dermatitis

/in , /by

What is Seborrheic dermatitis?

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition characterized by erythematous, scaly patches primarily in seborrheic areas—regions rich in sebaceous glands such as the scalp, face, and upper trunk. There are infantile and adult forms of seborrhoeic dermatitis.

 

 Who gets Seborrheic dermatitis?

Seborrhoeic dermatitis affects 3% to 12% of the population and has two main age distributions:   

Infants: Under 3 months old; usually resolves by 6-12 months.

Adults: It typically begins in late adolescence, is more common in males, and tends to peak during young adulthood and later in life. Various factors are linked to more severe cases in adults, including having oily skin, a family history of seborrhoeic dermatitis or psoriasis, and conditions causing immunosuppression, such as organ transplants, HIV, or lymphoma. Additionally, neurological and psychiatric disorders like Parkinson’s disease, depression, and epilepsy, as well as the use of neuroleptic medications, can contribute to its severity. Other contributing factors include PUVA therapy for psoriasis, lack of sleep, and stressful life events.

 

Causes of seborrhoeic dermatitis

The exact cause of seborrhoeic dermatitis is not fully understood. However, various factors are thought to be associated with the condition, including hormonal changes, fungal infections, nutritional deficiencies, and neurogenic factors. The proliferation of Malassezia yeast is believed to contribute to its development. Malassezia, a normal skin saprophyte, produces lipases and phospholipases that break down triglycerides in sebum into free fatty acids, which may trigger inflammation. Differences in skin barrier lipid composition and function may account for the varying manifestations of the condition. 

 

Clinical features of Seborrhoeic dermatitis

Infantile seborrhoeic dermatitis

Seborrhoeic dermatitis in infants, also known as cradle cap, features:

  • Diffuse, greasy, yellow scaling on the scalp.
  • The rash may extend to the armpit and groin folds.
  • Salmon-pink patches that may flake or peel.
  • Generally not itchy

Adult seborrhoeic dermatitis

Seborrheic dermatitis typically follows a chronic course characterized by episodic phases. Active phases may include symptoms such as burning and itching, while these are interspersed with inactive, asymptomatic periods. The condition usually flares in winter and improves with sun exposure in the summer. It manifests with a range of symptoms, from erythematous plaques with patchy scaling to greasy yellow crusts, and is commonly distributed in areas with hair and oily skin. The affected regions include:

  • Scalp (dandruff and itching)
  • Forehead/hairline and retro auricular area
  • Nasolabial fold, eyebrows, and periocular region (blepharitis with scaly, red eyelid margins)
  • Cheeks and chin
  • Presternal and interscapular regions
  • Axillae, under the breasts, umbilicus, and groin area

People with darker skin may show scaly, hypopigmented macules and patches in affected areas.

 

Diagnosis of Seborrhoeic dermatitis

Seborrhoeic dermatitis is usually diagnosed clinically based on lesion location, appearance, and behavior. If uncertain, a biopsy may be performed. Histological findings in seborrhoeic dermatitis typically include:

  • Parakeratosis in the epidermis
  • Plugged follicular ostia
  • Spongiosis (intercellular edema in the epidermis)
  • A sparse, perivascular, lymphohistiocytic inflammatory infiltrate in the dermis

 

Treatment of Seborrhoeic dermatitis

General Measures

  1. Patient Education:
    • Explain the nature of the condition and appropriate skincare routines.
  2. Lifestyle Modifications:
    • Diet: A high fruit intake may reduce symptoms.
    • Stress Management: Stress can trigger flare-ups, so managing stress is important.
  3. Many herbal remedies are used, but their effectiveness is unclear.

Specific Measures

  1. Keratolytics:
    • Salicylic Acid, Lactic Acid, Urea, Propylene Glycol: Used to remove scales.
  2. Topical Antifungal Agents:
    • Ketoconazole, Ciclopirox: Reduce Malassezia.
    • If resistant: Zinc Pyrithione or Selenium Sulfide.
  3. Mild Topical Corticosteroids:
    • Use for 1–3 weeks to reduce inflammation during acute flare-ups.
  4. Topical Calcineurin Inhibitors:
    • Pimecrolimus Cream, and Tacrolimus Ointment: Alternatives for long-term use, especially on the face.
  5. Resistant Cases in Adult :
    • Oral Itraconazole, tetracycline antibiotics, or phototherapy.
    • Low-Dose Oral Isotretinoin: Effective for severe cases.
  6. Roflumilast 0.3% Foam: Recently FDA-approved for use in patients aged 9 years and older.

 

Written by:

Atheer Alhuthaili, Medical Intern.

Revised by:

Naif Alshehri, Medical Intern.

References:

DermNet.

Amboss