### Date : 2024-06-22 12:47 ### Topic : Contact Dermatitis #medicine #dermatology ---- ### Contact Dermatitis Overview **Contact dermatitis** is a type of skin inflammation caused by direct contact with an irritant or allergen. It results in red, itchy, and sometimes painful rashes. There are two main types of contact dermatitis: irritant contact dermatitis and allergic contact dermatitis. ### Types of Contact Dermatitis 1. **Irritant Contact Dermatitis (ICD):** - Caused by direct chemical damage to the skin from irritants such as soaps, detergents, acids, or solvents. - Symptoms often appear shortly after exposure. 2. **Allergic Contact Dermatitis (ACD):** - Caused by an immune response to an allergen, such as poison ivy, nickel, fragrances, or certain preservatives. - Symptoms may take 12-48 hours to appear after exposure. ### Pathophysiology - **Irritant Contact Dermatitis:** - Non-immune-mediated response where irritants cause damage to the skin barrier, leading to inflammation. - **Allergic Contact Dermatitis:** - Delayed hypersensitivity reaction (Type IV) where the immune system recognizes an allergen as foreign, triggering an inflammatory response. ### Clinical Features **Common Symptoms:** - Redness (erythema) - Swelling (edema) - Itching (pruritus) - Pain or burning sensation - Dry, scaly, or cracked skin - Blisters or vesicles that may ooze and crust over ### Diagnosis **Clinical Evaluation:** - Detailed patient history, including recent exposures to potential irritants or allergens. - Physical examination of the affected skin areas. **Patch Testing:** - Used primarily for diagnosing allergic contact dermatitis. - Small amounts of potential allergens are applied to the skin under adhesive patches and left in place for 48 hours. The skin is then evaluated for reactions. **Example Case Study** **Patient Profile:** - **Name:** Jee Hoon Ju - **Age:** 28 - **Occupation:** Hairdresser **Medical History:** - **Symptoms:** Red, itchy rash on hands and forearms for the past week. No previous history of similar symptoms. - **Exposure:** Frequent use of hair dyes, shampoos, and other hairdressing chemicals. **Clinical Evaluation:** - **Physical Examination:** Red, scaly patches with some vesicles on the hands and forearms. **Patch Testing:** - Positive reaction to certain hair dye chemicals. **Diagnosis:** Based on the clinical presentation and patch testing results, Jee Hoon Ju is diagnosed with allergic contact dermatitis caused by hair dye chemicals. ### Management 1. **Avoidance of Irritants and Allergens:** - Identify and avoid the specific substances causing the dermatitis. - Use protective clothing or barriers (gloves) to minimize exposure. 2. **Topical Treatments:** - **Corticosteroids:** Topical corticosteroids to reduce inflammation and itching. - Mild cases: Hydrocortisone cream. - Severe cases: Stronger corticosteroids like clobetasol. - **Emollients:** Moisturizers to repair the skin barrier and reduce dryness. - **Topical Calcineurin Inhibitors:** For sensitive areas (face, genital areas) where corticosteroids may not be suitable. 3. **Systemic Treatments:** - **Antihistamines:** Oral antihistamines to relieve itching. - **Oral Corticosteroids:** For severe or widespread dermatitis. 4. **Lifestyle and Home Care:** - Keep the affected area clean and dry. - Avoid scratching to prevent secondary infections. - Use mild, fragrance-free soaps and detergents. ### Prognosis - **Irritant Contact Dermatitis:** Typically resolves within a few days to weeks after avoiding the irritant and with appropriate treatment. - **Allergic Contact Dermatitis:** May take longer to resolve and can recur with re-exposure to the allergen. Long-term management involves identifying and avoiding specific allergens. ### Conclusion Contact dermatitis is a common skin condition caused by exposure to irritants or allergens. Proper diagnosis involves identifying the offending substances, often through patient history and patch testing. Management includes avoiding triggers, using topical and systemic treatments to reduce symptoms, and implementing protective measures to prevent recurrence. With appropriate care, most cases of contact dermatitis can be effectively managed and resolved.