What is an inflammatory skin condition?
Inflammation of the skin is usually a symptom of an underlying condition like eczema or dermatitis, although it can also be caused by an allergic reaction such as contact dermatitis or a reaction to an insect bite. Often inflammatory skin conditions are due to a chronic autoimmune condition like lupus erythematosus or lichen planus. Mouth ulcers caused by a skin lesion in the mouth or an infection can become inflamed. Symptoms vary from mild irritation with itching, redness and discomfort, to severe with blisters, scaly patches of skin and weeping sores.
Examples of inflammatory skin conditions
Inflammatory skin conditions include:
- Eczema, a chronic itchy skin condition caused by inflammation of the epidermis or outer layer of skin. It is also known as atopic eczema or atopic dermatitis, as there is a predisposition due to an inherited atopic tendency, with a family history of three closely linked conditions: asthma, eczema and hay fever.
- Irritant contact dermatitis, which is caused by direct skin contact with an irritant like solvents and harsh chemicals.
- Allergic contact dermatitis, an allergic reaction caused by contact with a substance that triggers a delayed immune hypersensitivity reaction in response to a specific allergy such as to perfume, latex or nickel.
- Seborrhoeic dermatitis, also known as cradle cap in babies, is a scaly rash that usually affects areas of the face or scalp that are greasy or oily, causing peeling similar to dandruff.
- Neurodermatitis, a repeated rubbing or scratching due to a constant itch scratch cycle, causing a thickened pigmented patch of skin.
- Lichen planus, an abnormal immune reaction, in which the body’s immune cells attack self but may also be a reaction to a medication or to a viral infection. Symptoms include, papules (bumps on the skin) forming a rash with raised reddened patches and they can occur anywhere on the skin, particularly the wrist, ankles and lower back; also on mucous membranes like the mouth.
- Psoriasis a non-allergic, chronic automimmune skin condition that has a genetic predisposition, where certain cells of the immune system overproduce inflammatory chemicals that stimulate excessive growth and proliferation of keratinocytes (epidermal skin cells), causing thickening and scaling of the skin as well as inflammation. Symptoms including red scaly patches of skin ranging from mild to severe with psoriatic lesions covering large areas of the body and causing extreme itching, pain and discomfort.
- Discoid lupus erythematosus is a chronic autoimmune condition that affects the skin usually of the face, ears and scalp but can affect other parts. Symptoms include red scaly patches with sores and inflammation leaving and scarring.
- Mouth ulcers originally caused by injury to or infection of the skin, which develops into an inflammatory lesion.
How corticosteroids work
Corticosteroids are glucocorticoid steroid hormones that are produced naturally by the body and are involved in regulation of many functions including inflammatory and allergic reactions. Their anti-inflammatory action is based on blocking the production of chemicals that are inflammatory mediators, particularly prostaglandins and leukotrienes. They work by binding to a specific receptor in inflammatory cells like leukocytes and macrophages at sites of inflammation in the skin, and blocking the action of phospholipase A2, the first enzyme involved in the synthesis of prostaglandins and leukotrienes, as well as the cyclooxygenase enzymes (COX 1 and COX 2), that are specifically involved in prostaglandin production.
Synthetic corticosteroids that are used in topical corticosteroid medications mimic natural corticosteroids and work in the same way. These include triamcinolone a moderately potent corticosteroid, betamethasone, mometasone, hydrocortisone 17-butyrate, and clobetasol, which is the most potent of the synthetic corticosteroids. Some of these corticosteroids like triamcinolone also blocks formation of other inflammatory mediators, such as kinins, also histamine release which is the cause of itching, and also modifies the body's immune response.
Inhibiting production of inflammatory mediators has several anti-inflammatory and immunosuppressive effects, including preventing migration of inflammatory cells, which helps dampen down the inflammatory response; reducing capillary wall permeability and promoting vasoconstriction, which causes blood vessel narrowing, and helps reduce swelling and redness. Antipruritic actions help stops itching.
Application of topical corticosteroids
Corticosteroid medications are available in various applications to be used on different parts of the body and are suitable for different skin conditions. These include:
- A protective, emollient (soothing and moisturising) dental paste containing triamcinalone for mouth ulcers.
- Creams containing triamcinalone, mometasone, hydrocortisone, betamethasone and clobetasol are best used for moist lesions skin that is inflamed and itchy, as they can be rubbed into the skin without being greasy and have emollient (soothing and moisturising) properties.
- Ointments containing mometasone and clobetasol can be used for dry scaling and fissured (cracked due to dryness) lesions as they contain a mixture of oil and water that helps keep moisture in and preventing evaporation.
- Scalp lotion containing clobetasol for Inflammatory skin conditions of the scalp.