Contact Dermatitis
- Definition: Group of skin disorders caused by direct contact with a causative agent.
- Types:
- Chemical burns
- Irritant contact dermatitis
- Allergic contact dermatitis
- Contact stomatitis and contact cheilitis
- Protein contact dermatitis
- Systemic contact dermatitis
- Common Causes: Occupational exposure, particularly in cleaners, healthcare workers, food handlers, caterers, hairdressers, and computer users (computer mouse dermatitis).
Appearance
- Highly variable and can affect any body area.
- Features:
- Redness (erythema)
- Blisters (vesicles or bullae)
- Swelling (oedema)
- Dryness or scaling
- Cracks (fissuring)
- Lichenification (thickened, lined skin)
- Pigmentation changes (hyperpigmentation or hypopigmentation)
- Secondary Changes:
- Scratch marks (excoriation)
- Crusting
- Pustules (bacterial infection)
Diagnosis
- History:
- Eczematous rash in contact area with the putative cause
- Asymmetrical distribution, e.g., one hand more affected
- Types:
- Chemical Burn: Single exposure to a toxic agent.
- Irritant Dermatitis: Single or repetitive exposure to irritants; common in individuals with compromised skin barrier function.
- Allergic Dermatitis: Occurs after initial tolerance; can spread beyond contact areas.
- Contact Stomatitis/Cheilitis: Affects mouth and lips.
- Protein Contact Dermatitis: Immediate urticaria followed by dermatitis.
- Systemic Contact Dermatitis: After ingestion of previously causing allergen; results in symmetrical rash.
- Tests:
- Patch tests
- Open application test
Treatment
- Avoidance:
- Identify and avoid causative agents
- Avoid soap; use pH-balanced cleansers
- Wear appropriate gloves for protection
- Dry skin carefully after washing
- Medications:
- Short course of topical corticosteroids
- Frequent application of emollients
- Severe cases: Short course of systemic corticosteroids (e.g., oral prednisone)
- Chronic cases: Phototherapy or immunosuppressive agents (e.g., methotrexate, ciclosporin, azathioprine)