What is contact dermatitis? Symptoms
Contact dermatitis (CCD), also known as contact eczema, is a local inflammatory reaction of the skin. It results from hypersensitivity to an external stimulus, usually a chemical that is foreign to the body [1]. The symptoms of CFS are slightly more common in women than in men. It is the predominant occupational skin disease, but it occurs not only in adults who are exposed to irritants in the workplace. It is also diagnosed in children, even in the neonatal period [1]. Contact dermatitis (in reaction to mercury) was first described in the late 19th century [1].
With KZS, symptoms such as:
- itching,
- swelling,
- burning of the skin,
- erythema and blisters on the skin,
- scaling of the epidermis,
- skin cracking,
- lichenisation, or thickening of the skin (in the chronic form of KZS) [1].
The disease progresses in five phases:
- erythematous-edematous ,
- exudative,
- scab formation,
- exfoliation,
- healing [1].
Not only allergens – the causes of KZS
There are different types of contact dermatitis: allergic (in reaction to contact allergens – haptens), irritant (in reaction to irritants), photoallergic or phototoxic (in reaction to ultraviolet radiation) [1,2]. In the case of irritation – unlike in allergy – symptoms appear after the first exposure to the irritant. Both allergic and non-allergic contact eczema can be divided into acute and chronic.
Allergic contact dermatitis
This type of AS is quite common – it is estimated to affect 15-20% of people worldwide [2]. It is most commonly caused by nickel, preservatives and fragrance additives [2]. There are different groups of contact allergens:
- metals, e.g. nickel, cobalt, chromium, palladium,
- preservatives, fragrances and dyes, e.g. formaldehyde, thimerosal, paraphenylenediamine (artificial henna), balsam of Peru, essential oils,
- components of medicines and cosmetics, e.g. lanolin, neomycin, benzocaine,
- vulcanisation accelerators and rubber antioxidants, e.g. latex, lycra,
- uncured epoxy resins [1,3,4].
Allergic contact dermatitis is caused by activation of the immune system in a late-type hypersensitivity mechanism. This means that skin lesions appear not immediately, but within 24-48 hours after exposure to the allergen [3]. Initially, they cover only the area of skin that was in direct contact with the allergen, but over time they can spread [3].
Nickel allergy
Nickel – a major contact allergen – is widespread in the environment and released from many metallic objects of everyday use [3]. It is found in cutlery, coins, medical implants, jewellery and other accessories (buckles, watches) and even in food [3]. It is responsible for more cases of allergic CRS than all other metals combined [6]. It sensitises 17% of women and 3% of men [3]. Some people develop skin eczema after only brief contact with nickel [6]. The metal can cause not only skin lesions, but also gastrointestinal, respiratory and neurological symptoms, which is referred to as systemic nickel allergy syndrome (UZAN) [6].
Latex allergy
Latex is also a well-known contact allergen. Although the incidence of latex allergy is less than 1%, there is a much higher incidence of sensitisation among those who come into daily contact with this material. This includes, for example, healthcare workers wearing latex gloves – interestingly, also patients who have undergone multiple surgical procedures [7]. Latex can even cause very severe reactions – including anaphylaxis – in particularly sensitive individuals, especially in atopics. Most commonly, however, it causes dryness, burning, astringency, itching and redness of the skin, as well as inflammatory lesions (urticarial blisters) [7].
Allergy to cosmetics
Cosmetics are often the cause of allergic contact dermatitis. Allergic contact eczema is experienced by 5.8% of women (for men, the percentage is less than half) [9]. It must be assumed, however, that these figures are underestimated, as some people with mild reactions do not visit a doctor at all.
Some of the more important allergens found in cosmetics include:
- fragrances, e.g. geraniol, oakmoss (Evernia prunastri), cinnamaldehyde,
- preservatives, e.g. parabens, timerosal,
- dyes, e.g. aromatic amines (p-phenylenediamine – PPD, p-toluenediamine – PTD),
- substrates and solvents, e.g. lanolin, propylene glycol, beeswax, rosin (in hair removal products) [8].
Allergy to cosmetics, or rather the substances contained in them, can manifest as swelling, redness of the skin, hives, as well as the occurrence of erosions and oozing blisters [8].
Irritant contact dermatitis
Irritant contact dermatitis, unlike allergic contact dermatitis, is in no way related to sensitisation. It can occur in anyone who has been in contact with an irritant in sufficiently high concentrations. The irritant causes damage to keratinocytes (which produce keratin in the skin) and other epidermal cells. Inflammatory mediators are released from the damaged cells, leading to inflammation of the skin [5]. Irritants that have been linked to the occurrence of KZS include:
- cleaners and detergents,
- oils, varnishes, adhesives and solvents,
- paints and inks,
- fertilisers and pesticides,
- wood preservatives,
- glass fibres,
- acids and alkalis,
- soldering pastes,
- disinfectants and alcohols,
- oxidising agents and bleaching agents.
Contact dermatitis from irritation is favoured by work in wet environments, i.e. cleaning, hairdressing and cosmetics, for example [5]. Examination of peripheral blood lymphocytes in a group of hairdressers with contact eczema showed DNA damage to the cell nuclei. This damage was caused by irritants and hair dyes [5].
Photoallergic and phototoxic reactions
A photoallergic or phototoxic reaction, or photodermatosis, is caused by light. However, for such a reaction to occur, an external agent (cosmetic, drug, plant or its sap) must be present in addition to the radiation itself. This factor sensitises the skin to light [8,10]. A photoallergic reaction (rarer) occurs only in sensitised individuals, whereas virtually everyone is exposed to a phototoxic reaction [10].
Symptoms of photodermatosis appear within minutes or hours of exposure to radiation. The risk of their occurrence is increased by excessive sunbathing [8]. The most severe reactions occur on exposed skin areas: face, neck, décolleté [10].
Photoallergic contact eczema usually takes the form of papular eruptions accompanied by itching of the skin [10]. The phototoxic reaction, on the other hand, is characterised by erythema, oedema, blisters – resembling a sunburn. It can leave behind permanent discolouration [10].
Substances with photosensitising properties are mainly found in:
Cosmetics:
- sunscreens (p-aminobenzoic acid – PABA, benzophenones),
- fragrances (6-methylcoumarin, bergamot oil, ambrette musk, cinnamaldehyde),
- preservatives (bithionol, digluconate, triclosan).
Medicines:
- the painkillers (ibuprofen, ketoprofen, naproxen),
- Antibacterials (azithromycin, doxycyline, tetracycline),
- antifungal (traconazole, ketoconazole),
- antiparasiticides (quinine, chloroquine),
- antidiabetics (metformin, glipizide),
- antihypertensive and cardiovascular (amiodarone, diltiazem),
- anti-allergic (cetirizine, loratadine),
- neurological, psychotropic and sedative (doxepin, carbamazepine, promethazine) [10,11].
Photosensitising plant substances include diallilodisulphide (in garlic), psoralens (in garden lovage, watercress, celery), lactone sesquiterpenes (in arnica, goldenrod, calendula, chamomile, sunflower, daisy, yarrow) [10,11].
Contact dermatitis – treatment, diagnosis
The diagnosis of contact dermatitis is based on patch tests with a specific allergen or photoallergen [1,10]. In treatment, it is crucial to eliminate contact with the sensitising or irritating substance as soon as possible [1].
In terms of medication, topical glycocorticosteroids (GCS) or calcineurin inhibitors are mainly applicable, which can be used in such sensitive skin areas as the face, neck and groin [1]. These drugs come in the form of solutions, ointments and creams. Ointment for contact dermatitis is recommended for dry skin lesions. On the other hand, when vesicles and exudate are present, a solution or cream is recommended [1].
In severe AS (with acute inflammation and involvement of large areas of skin), oral glycocorticosteroids are included. However, in chronic forms of the disease, emollients, keratolytics (creams with polidocanol and urea) and vaseline are used [1].
Skin-drying and pruritus-relieving compresses (with 0.9 per cent sodium chloride solution, boric acid or aluminium acetate), as well as antipruritic and antihistaminic drugs, are also helpful [1].
