Contact Dermatitis may be due to an irritant or an allergen.
- Irritant Contact Dermatitis
Irritant contact dermatitis accounts for 80% of all contact dermatitis reactions.
It occurs when the skin comes in contact with a substance that acts as irritant. Almost any substance under the right circumstances can act as an irritant
Acute Irritant Contact Dermatitis
Strong toxic chemical such as an acid or alkali.
The rash occurs within minutes to hours after exposure and in most cases healing occurs soon after exposure.
- Sharp bordered rash
- Skin sloughing.
Chronic Cumulative Irritant Contact Dermatitis
Repeated exposure to low-level irritants, such as soaps or shampoos.
The rash may take weeks, months, or even years to develop.
- Poorly-defined bordered rash
Examples of irritants:
- Dribble rash around the mouth or on the chin in a baby, or in older children due to licking; the cause is saliva, which is alkaline.
- Napkin dermatitis due to urine and faeces.
- Chemical burns from strong acids (eg. hydrochloric acid) and particularly alkalis (eg. sodium or calcium hydroxide).
- Hand dermatitis caused by excessive exposure to water, soaps, detergents, bleaches and polishes.
- Dermatitis on a finger underneath a ring. Soaps, shampoos , detergents and hand creams accumulate under the ring
- Rubber gloves or the powder or sweat or tiny quantities of chemicals inside them
- Rubber may result in latex or rubber antioxidant allergy.
- Fibre glass may cause direct mechanical/frictional damage.
- Dry cold air may cause dry irritable skin (winter itch)
- Cosmetics(mainly gels and solutions) may irritate sensitive facial skin.
Avoiding the irritant should allow the rash to clear in two to four weeks. Creams or medication can help reduce itching.
2. ALLERGIC CONTACT DERMATITIS—
Allergic contact dermatitis is inflammation of the skin manifested by varying degrees of erythema, edema, and vesiculation.
It is a delayed type of induced sensitivity (allergy) resulting from cutaneous contact with a specific allergen to which the patient has developed a specific sensitivity .
- Metals( nickel or cobalt) in jewellery
- Cosmetics(fragrances, hair dye and nail varnish)
- Rubber, including latex
- Textiles, particularly the dyes and resins that are contained in them
- Strong adhesives ( epoxy resin adhesives)
- Some plants(chrysanthemums, daffodils, tulips and primula)
- Some topical medicines
- Avoid the cause
- Topical corticosteroids
- Oral corticosteroids