Seborrheic Dermatitis

Seborrheic dermatitis is a chronic, recurrent inflammatory skin disorder that primarily affects areas of the body rich in sebaceous (oil) glands. It is strongly associated with overgrowth of Malassezia species (a normal skin yeast), together with an abnormal inflammatory response of the skin. The condition is not contagious, not caused by poor hygiene, and is not life-threatening, but it often causes persistent itching, visible scaling, and cosmetic concerns that can affect quality of life.

Pathophysiology (Brief)

Main mechanism:

Inflammatory reaction to Malassezia species in genetically susceptible individuals.

Contributing factors:

• Increased sebaceous gland activity

• Overgrowth of Malassezia yeast

• Individual immune response

• Genetic predisposition

• Cold weather and low humidity

• Emotional stress

• Neurological disorders (e.g., Parkinson disease)

• HIV infection or other immunosuppressive conditions

Signs & Symptoms

Typical lesions:

• Erythematous (red) macules and plaques

• Greasy yellow or white scales

• Mild to severe itching (pruritus)

• Flaking of the skin (dandruff on the scalp)

Common sites:

• Scalp

• Face (eyebrows, nasolabial folds, beard area)

• Behind the ears

• Chest (sternal area)

• Upper back

• Axillae

• Groin

Other findings:

• Oily skin

• Burning or irritation

• Recurrent episodes with periods of remission

• Cosmetic embarrassment due to visible scaling

Diagnostic Criteria

Clinical diagnosis based on:

• Characteristic greasy scaling over erythematous skin

• Distribution in sebaceous gland-rich areas

• Chronic or recurrent course

Supporting signs:

• Dandruff involving the scalp

• Symmetrical distribution

• Mild to moderate itching

• Improvement with antifungal treatment

Investigations

Diagnosis is usually clinical.

Investigations may be considered when the diagnosis is uncertain or disease is severe.

Recommended tests

• Usually no laboratory tests required

• HIV testing in severe, extensive, or treatment-resistant disease

• Skin scraping with potassium hydroxide (KOH) preparation if fungal infection is suspected

Special tests

• Skin biopsy (rarely required)

• Fungal microscopy when diagnosis is unclear

Treatment

Treatment aims to reduce inflammation, control Malassezia overgrowth, relieve symptoms, and prevent recurrence, since the condition commonly relapses.

Non-Pharmacological Treatment

• Patient education about the chronic recurrent nature of the disease

• Wash affected areas regularly using mild cleansers

• Avoid harsh soaps and irritating skin products

• Reduce emotional stress where possible

• Maintain good skin hygiene

• Avoid excessive scratching

Pharmacological Treatment

Skin (Face, Chest, Back, Axilla, Groin)

Clotrimazole cream (topical) — apply every 12 hours for 4–16 weeks

OR

Miconazole cream (topical) — apply every 12 hours for 4–16 weeks

AND

Hydrocortisone cream 0.5% (topical) — apply every 12 hours for 4–16 weeks

Scalp

OR

Ketoconazole shampoo — use 3 times per week for not less than 3 months

Complications

• Recurrent disease

• Secondary bacterial skin infection

• Persistent itching

• Sleep disturbance due to pruritus

• Cosmetic and psychological distress

Prevention

Although seborrheic dermatitis cannot always be prevented, recurrence can be reduced by:

• Regular use of medicated shampoos in affected individuals

• Early treatment of flare-ups

• Good skin hygiene

• Avoiding harsh skin products

• Managing stress

• Appropriate management of underlying conditions such as HIV infection

Patient Counselling (Important)

• The condition is not contagious.

• It is not caused by poor hygiene.

• Treatment controls symptoms but does not permanently cure the condition.

• Regular treatment may be required to prevent recurrence.

• Symptoms often worsen during periods of stress or cold weather.

• Seek medical review if symptoms become severe, widespread, or fail to improve with treatment.