Seborrheic dermatitis is a relatively common skin condition affecting many individuals. Typically, those with this condition experience an imbalance between skin moisture and oil production. Daily cleansing may be neglected or challenging, yet it cannot be simplified—skin protection must also be prioritized. So, what causes seborrheic dermatitis? What are the underlying reasons for developing this condition?
1. Impaired Fat Metabolism
This condition arises as a secondary chronic inflammation following excessive sebum secretion.Non-pathogenic bacteria on the skin break down sebum into free fatty acids, triggering inflammation.
2. Endocrine Imbalance
Hormonal irregularities increase sebum production and alter its chemical composition, reducing its antibacterial properties. Elevated androgens, for instance, disrupt the skin's microbial balance, allowing normal flora like Staphylococcus, Malassezia, and Streptococcus to proliferate excessively and cause infection.
3. Poor Lifestyle Habits
Frequent late nights, neglecting personal hygiene, and failing to cleanse the skin promptly allow sweat and sebum to accumulate on the skin surface over time. This leads to putrefactive decomposition, creating an environment conducive to bacterial growth and ultimately triggering infections that cause seborrheic dermatitis.
4. Poor Dietary Habits
Regular consumption of high-fat or overly stimulating foods, dietary deficiencies in vitamin B1, and excessive alcohol consumption can all trigger or exacerbate seborrheic dermatitis.
5. Disease Factors
In patients with acne, concurrent Corynebacterium infections may occur. Corynebacteria break down fatty acids, irritating the skin and worsening infection. Alternatively, excessive proliferation of oval bacteria invading healthy skin can trigger seborrheic dermatitis.
6. Other Factors
External irritants like frequent scratching, friction, alkaline cleansers, and various physical/chemical stimuli; excessive mental stress; and genetic predisposition can all exacerbate seborrheic dermatitis flare-ups.
7. Symptoms of Seborrheic Dermatitis
1. Commonly Affected Areas
Seborrheic dermatitis occurs in hairy, sweaty, and sebum-rich areas, primarily where sebaceous glands are abundant: scalp, eyebrows, eyelids, nasolabial folds, behind the ears, anterior sternum, back, perineum, and armpits.
2. Characteristic Erythematous Scaling
The primary symptom is erythematous scaling. Lesions appear as bright red or yellowish-red patches covered with greasy scales, sometimes accompanied by exudation and crusting.
3. Skin Papules
Affected skin areas are often oily with enlarged sebaceous follicles. Typical lesions include yellow papules or macules with well-defined borders, covered by greasy scales. Severe cases may involve the entire body.
4. Skin Itching
The greasy, foul-smelling crusts in seborrheic dermatitis areas cause itching. Improper handling, friction, or scratching often leads to complications like folliculitis, boils, or lymphadenitis.
5. Hair Loss
Seborrheic dermatitis on the scalp may present with greasy, foul-smelling crusts, occasional exudation, and hair loss. Gradual thinning occurs, most noticeable on the crown, often accompanied by otitis externa and blepharitis.
6. Characteristics of Infantile Seborrheic Dermatitis
In newborns and infants, yellowish-white crusts (cradle cap) appear on the scalp. Follicular red papules may cluster on the forehead and eyebrows, forming yellowish-white crusts. The condition may even extend to the trunk.