Seborrheic Dermatitis

Seborrheic dermatitis is characterized by red plaques and greasy, yellowish scales in parts of the body that are rich in sebaceous glands. It’s distributed symmetrically in the affected area, has a seasonal pattern (more prevalent in the winter), and may aggravate upon sleep deprivation and stress.

Patients with immunosuppression such as those with AIDS usually present with more severe disease that doesn’t respond to treatment. They also present with the disease in unusual sites such as the extremities. They may also present with other skin conditions such as rosacea, psoriasis, and acne.

The exact mechanism of how seborrheic dermatitis occurs isn’t yet well-understood, but studies have implicated several factors that may be associated with this skin disorder. These factors include fungal colonization, sebaceous gland activity, individual susceptibility, and nutrition.

Fungal Colonization

The etiologic agent most commonly implicated in the causation of seborrheic dermatitis is Malassezia, which are yeasts who thrive on oils and lipids and thus are commonly found in the sebaceous areas of the body.

These yeasts have lipase activity, or the ability to break down lipids for use in their own metabolism, releasing unsaturated fatty acids which cause impairments in the processing of the skin such as in keratinocyte differentiation.

These metabolites also play a role in prolonging the immune response by producing proinflammatory cytokines and encouraging the recruitment of pro-inflammatory mediators like neutrophils.

Sebaceous Gland Activity

Sebaceous glands or oil glands occur on all body parts except the palms and soles. Sebum or oil is produced at a highest rate on the scalp, face, and scalp, with the amount produced mediated by hormones like androgens.

A high activity of sebaceous gland is implicated in the development of seborrheic dermatitis, along with abnormal lipid composition that encourage the growth of Malassezia.

Individual Susceptibility

Some individuals are also more prone to developing seborrheic dermatitis than others. There are numerous factors behind this, which include the following:

Epidermal Barrier Integrity – Impairments in epidermal barrier integrity contributes to the aggravation of seborrheic dermatitis, as evidenced by the structural findings in patients with this skin disorder. These structural findings include changes in corneocyte shape and corneodesmosomes and disrupted lipid lamellar structure, which further encourage the growth of Malassezia.

Immune Response – Seborrheic dermatitis is more prevalent and more severe in cases of immune suppression, especially in patients living with HIV/AIDS. No difference may be found in immunosuppressed patients and normal patients when it comes to Malassezia growth, so it’s likely that an immune or inflammatory reaction is the reason for this pattern of prevalence and severity.

Other Factors – Genetic factors, neurogenic factors and emotional stress, and nutrition are also thought to be associated with seborrheic dermatitis.

The therapeutic objectives of the treatment options for this skin disorder include relief of its symptom, especially itching, and the prevention of remission by promoting long-term therapy.

A dermatologist typically prescribes topical antifungal (including a medicated shampoo) and anti-inflammatory agents. These are chosen on the basis of efficacy, side effects, compliance, and the age of the patient.

Seborrheic dermatitis is a disease that affects the seborrheic areas of the body, belonging to the same spectrum of dermatological diseases as dandruff. They both manifest as itchy, flaky skin but they may be differentiated based on the following:

Seborrheic Dermatitis

• Affects the scalp as well as other seborrheic areas like the face, retro-auricular area, and the upper chest
• With visible signs of inflammation such as red skin

Dandruff

• Restricted to the scalp
• No visible signs of inflammation