Contact dermatitis is an inflammation of the surface of the skin caused by exposure either to an irritant or an allergen – something that the skin is allergic to – like poison ivy. Dermatitis and eczema are two terms used to describe the same pattern of inflammation. It causes red, itchy skin which may also blister. Contact dermatitis describes inflammation which is caused by contact with something in the environment. It may sometimes be referred to as contact eczema.
The dermatitis is generally confined to the site of contact with the allergen, although severe cases may extend outside the contact area or it may become generalised. Sometimes the allergen is transmitted from the fingers so unexpected sites can be affected eg the eyelids and genitals. Dermatitis is unlikely to be due to a specific allergen if the area of skin most in contact with that allergen is unaffected. The affected skin may be red, swollen and blistered or dry and bumpy.
Some typical examples of allergic contact dermatitis include –
- An eczema of the wrist underlying a watch strap due to contact allergy to nickel
- An eczema of the lower leg when ankle strapping has been removed due to contact allergy to rosin in the adhesive plaster
- Hand dermatitis caused by rubber accelerator chemicals used in the manufacture of rubber gloves
- Itchy red face due to contact allergy with methylisothiazolinone, a preservative in wash-off hair products and baby wipes.
Types & Causes of Contact Dermatitis
- Irritant contact dermatitis – Any substance can be an irritant to the skin, especially if the concentration and duration of contact are sufficient. Most irritants are chemical in nature. Irritants such as soaps, detergents, deodorants, lotions, and perfumes often require repeated or prolonged contact to produce inflammation. Stronger irritants such as acids or alkalis are so damaging that they will injure the skin immediately on contact. If daily exposure to mild irritants is continued, normal skin may become hardened or tolerant to this trauma and contact may be continued without further evidence of irritation.
- Allergic contact dermatitis – Allergic contact dermatitis, on the other hand, requires skin contact with an allergen (i.e. any product, plant or chemical to which you are allergic). The oils of plants like poison ivy or sumac, and metals like gold and nickel are very common allergens. The reaction is typically delayed. A period as long as 5 to 21 days may elapse after your first exposure to the allergen before you see a reaction. However, the reaction time after re-exposure typically occurs within 12 days.
Common irritants include solvents, industrial chemicals, detergents, fumes, tobacco smoke, paints, bleach, woolen fabrics, acidic foods, astringents and other alcohol (excluding cetyl alcohol) containing skin care products, and some soaps and fragrances. Allergens are usually animal or vegetable proteins from foods, pollens, or pets.
Sometimes substances such as proteins in fruit and vegetables can cause an immediate allergic reaction leading to itchy skin swellings known as contact urticaria (hives), which in turn can aggravate your dermatitis.
- Certain Occupation – Some occupations have more exposure to chemicals or substances that can result in sensitization and cause allergic contact dermatitis. Examples of these include dental workers, health care workers, florists, hairdressers, and machinists.
- Genetic – People with a tendency to asthma, eczema and hay fever develop irritant contact dermatitis more easily than others, and this tendency does run in families.
- Hobbies – Hobbies may be the source of allergic contact dermatitis. Examples include woodworking with exotic tropical woods or processing film using color-developing chemicals that may provoke cutaneous lesions of lichen planus from direct skin exposure.
- Medications (both self-prescribed and physician-prescribed) are important causes of allergic contact dermatitis. The workplace nurse may dispense ineffective and sensitizing topical preparations, such as thimerosal (Merthiolate), which may change a simple abrasion into a severe case of allergic contact dermatitis. Individuals may develop allergy to preservatives in medications and/or to the active ingredients in topical medications, especially neomycin and topical corticosteroids.
Contact dermatitis cannot be caught from nor spread to other people.
Symptoms
Contact dermatitis symptoms can range from mild redness and dryness to severe pain and peeling that can be disabling.
Allergic contact dermatitis symptoms include –
- Reddening of skin (either in patches or all over the body)
- Intermittent dry, scaly patches of skin
- Blisters that ooze
- Burning or itching that is usually intense without visible skin sores (lesions)
- Swelling in the eyes, face, and genital areas (severe cases)
- Hives
- Sun sensitivity
- Darkened, “leathery,” and cracked skin
Allergic contact dermatitis can be very difficult to distinguish from other rashes.
Irritant contact dermatitis symptoms include –
- Mild swelling of skin
- Stiff, tight feeling skin
- Dry, cracking skin
- Blisters
- Painful ulcers on the skin
Symptoms vary depending on the cause of dermatitis.
Complications
- Chronic itchy, scaly skin – A skin condition called neurodermatitis (lichen simplex chronicus) starts with a patch of itchy skin. As a person scratchs the area, which makes it even itchier. Eventually, he or she may scratch simply out of habit. This condition can cause the affected skin to become discolored, thick and leathery.
- Infection – If you repeatedly scratch a rash, the affected person may cause it to become wet and oozing. This creates a good place for bacteria or fungi to grow and may cause an infection.
Treatment
Symptomatic Treatment – Emollients or moisturizers help keep the skin moist, and also help skin repair itself. They protect the skin from becoming inflamed again. They are a key part of preventing and treating contact dermatitis. Examples include:
- Petroleum jelly
- Vanicream
- Cetaphil
- Eucerin
Medications – In cases where the symptoms are severe, corticosteroids applied to the skin or taken orally are used. Contact dermatitis that leads to a bacterial skin infection is treated with antibiotics. Common antihistamines include –
- Diphenhydramine (Benadryl)
- Hydroxyzine (Atarax)
- Cetirizine (Zyrtec)
- Loratadine (Claritin)
- Fexofenadine (Allegra)
Phototherapy – Individuals with chronic allergic contact dermatitis that is not controlled well by topical corticosteroids may benefit from psoralen plus ultraviolet-A (PUVA) treatments. Psoralen is a photosensitizer that is ingested prior to light exposure. Narrow-band UVB phototherapy may be as effective.
Lifestyle Changes –
For allergic contact dermatitis –
- Avoid contact with substances that cause the skin rash.
- Wash any area that comes into contact with allergic substances.
- Learn to recognize poison oak and poison ivy.
For irritant contact dermatitis –
- Wear cotton gloves under rubber gloves for all wet work. Use plain petroleum jelly to protect the skin. Reapply the petroleum jelly two or three times a day and after washing your hands.
- Avoid contact with substances that irritate the skin.
- Use mild soaps.
- Use hand creams and lotions frequently.
Alternative Treatment
Fish oil – In one study, people taking fish oil equal to 1.8 g of EPA (one of the omega-3 fatty acids found in fish oil) had significant reduction in symptoms of contact dermatitis after 12 weeks. Researchers think that may be because fish oil helps reduce leukotriene B4, an inflammatory substance that plays a role in dermatitis.
Probiotics may boost the immune system and control allergies, especially in children. In fact, studies show that taking probiotics during pregnancy, or early infancy, can protect against the development of dermatitis.
Vitamin C can act as an antihistamine. In one study, it helped reduce symptoms of dermtits, but more studies are needed.
Flavonoids, antioxidants found in dark berries and some plants, have anti-inflammatory properties, strengthen connective tissue, and may help reduce allergic reactions.
Borage oil, like evening primrose oil, contains the essential fatty acid GLA, which acts as an anti-inflammatory.
Evening primrose oil -In some studies, evening primrose oil helps reduce the itching associated with dermatitis.
Bromelain, an enzyme derived from pineapple, helps reduce inflammation. Bromelain can have a blood-thinning effect.
Hydrotherapy Remedies – Itching may persist when medications wear off in between doses. Symptoms of allergic reactions may be stronger than those associated with irritant contact dermatitis. For additional relief of discomfort, patients can take cool showers or therapeutic baths.
A combination of Licorice root, DHEA and Pregnenolone may be able to substitute for Cortisone if the patient cannot tolerate this medication.
Vitamin A is very important for skin and membranes.
Quercetin is very important for three reasons: it prevents the release of histamine; it inhibits production of leukotrienes; it is an effective treatment for inflammation.
Witch Hazel can reduce inflammation. However, for all areas with eruptions (vesicles), the best kind may be one without alcohol.
St. John’s wort used as a topical cream.
Reference –
https://www.aad.org/public/diseases/eczema/contact-dermatitis
https://www.nlm.nih.gov/medlineplus/ency/article/000869.htm
http://www.mayoclinic.org/diseases-conditions/contact-dermatitis/basics/definition/con-20032048
http://www.nhs.uk/conditions/eczema-(contact-dermatitis)/Pages/Introduction.aspx
http://www.emedicinehealth.com/contact_dermatitis/article_em.htm
http://www.webmd.com/skin-problems-and-treatments/contact-dermatitis
https://my.clevelandclinic.org/health/diseases_conditions/hic_Contact_Dermatitis
http://www.britishskinfoundation.org.uk/SkinInformation/AtoZofSkindisease/ContactDermatitis.aspx
http://www.aafa.org/page/contact-dermatitis.aspx