INFLAMMATORY DISORDERS OF SKIN – Dermatitis (Causes and Risk factors, Types, Pathophysiology, Clinical Manifestations, Diagnostic Evaluations and Management)
INFLAMMATORY DISORDERS OF SKIN – Dermatitis (Causes and Risk factors, Types, Pathophysiology, Clinical Manifestations, Diagnostic Evaluations and Management)
DERMATITIS
Dermatitis is inflammation of the upper layers of the skin, causing itching, blisters, redness, swelling, and often oozing, scabbing and scaling. The term eczema is sometimes used for dermatitis. It is an inflammatory reaction of skin to physical, chemical or biological agents. Epidermis is damaged by repeated physical and chemical irritations. It may be acute or chronic.
CAUSES AND RISK FACTORS
- Heredity
- Dryness of skin
- Interaction b/w a combination of immune system, physical environment and genetic factors
- Irritants and allergens like rubber, cosmetic allergies etc.
- Contact with a particular substance, certain drugs
- Family history of allergic conditions like food allergy, asthma etc
- Varicose veins
- Constant scratching
- Fungal infections
- Exposure to environment allergens and irritants
- Nickel and gold in jewellery
- Emotional stress
TYPES OF DERMATITIS
Contact Dermatitis
Contact dermatitis is skin inflammation caused by direct contact with a particular substance – such as poision ivy; jewelry containing nickel; and certain cleaning products, perfumes and cosmetics. The allergic reaction of the skin mediated by delayed hypersensitivity and occurs to a substance which comes in contact with the surface of skin. The rash is very itchy, is confined to a specified area, and often has clearly defined boundaries.
TYPES OF CONTACT DERMATITIS
Substances can cause skin inflammation by one of two mechanisms – irritation (irritant contact dermatitis) or allergic reaction (allergic contact dermatitis)
1. Irritant contact dermatitis
This reaction occurs when a substance damages skin’s outer protective layer. This type of dermatitis, which accounts for 80% of all cases of contact dermatitis, occurs when a chemical substance causes direct damage to the skin. Irritant contact dermatitis is more painful than itchy.
CAUSES
Common offenders include harsh soaps, chemical solvents, and cosmetics or skin products, including deodorant. Skin can also be irritated by body fluids (urine and saliva). People vary in the sensitivity of their skin to irritants. Exposure produces red, dry, itchy patches, often on hands, fingers or face.
2. Allergic Contact Dermatitis: it occurs when a substance to which patient is sensitive (allergen) triggers an immune reaction in skin. Allergic contact dermatitis produces a red rash, bumps and sometimes blisters when severe. After a person is sensitized, the next exposure causes intense itching and dermatitis within 4 to 24 hours, although some people, particularly older people, do not develop a reaction for 3 to 4 days.
CAUSES
The most common include substances found in plants such as poison ivy, rubber (latex), antibiotics, antihistamines, hair removing chemicals, deodorants, after shave lotions, perfumes, fragrances, preservatives, and some metals (such as nickel and cobalt). About 10% of women are allergic to nickel, a common component of jewelry. Even ointments, creams and lotions used to treat dermatitis can cause such a reaction.
PATHOPHYSIOLOGY
Causes (irritants and allergens) ---------- complex chain of events ------- proliferation and activation of T cells --- release of cytokines and other inflammatory mediators --- itching, swelling and pain
CLINICAL MANIFESTATIONS
Signs and symptoms of contact dermatitis include:
- Red rash or bumps
- Rash varies from a mild, short-lived redness to severe swelling and large blisters
- Itching, which may be severe
- Dry, cracked, red patches, which may resemble a burn
- Blisters, draining fluid and crusting in severe reactions
- Skin rash limited to an exposed area – for example, directly under a watchband
- Pain or tenderness
DIAGNOSTIC EVALUATIONS
The key to successful treatment of contact dermatitis is identifying what’s causing symptoms. Doctors rely on two chief strategies to determine the cause:
A thorough medical history and physical exam
A patch test (contact delayed hypersensitivity allergy test)
MANAGEMENT
Treatment is not effective until there is no further contact with the substance causing the problem. Once the substance is removed, the redness usually disappears after a week. Blisters may continue to ooze and form crusts, but they soon dry. Residual scaling, itching, and temporary thickening of the skin may last for days or weeks. Key treatment strategies for contact dermatitis include:
Avoiding the irritant or allergen: the key to avoidance involves identifying what’s causing symptoms and then eliminating exposure to the culprit. It may take two to four weeks for skin reaction to clear up.
Applying anti-itch creams or wet compresses. In mild to moderate cases, self-care measures, such as using over-the-counter creams containing hydrocortisone or applying wet dressings can help relieve redness and itching. In addition, small areas of dermatitis can be soothed by applying pieces of gauze or thin cloth dipped in cold water or aluminum acetate (Burow solution) several times a day for an hour. Larger areas may be treated with short, cool tub baths with or without colloidal oatmeal.