Irritative contact dermatitis

What is it

Irritant contact dermatitis (DIC) is an inflammatory reaction of the epidermis that develops following exposure to chemical compounds, natural or artificial, with irritating action. In its onset a specific immunological response is not called into question (as happens, instead, in the case of allergy to latex, metals, particular fabrics, dyes or other substances), but only an abnormal stress of the skin.

In general, DIC affects adults who come into direct contact with substances at risk in the workplace or home (solvents, detergents, detergents, disinfectants, synthetic resins, plant or animal toxins, oils, abrasive powders, etc.).

Everyone can be affected, but it is mainly experienced by subjects characterized by sensitive, delicate or fragile skin and, in particular, those who suffer or have suffered from atopic dermatitis in childhood. Less frequently, it can also affect children (for example, if irritating plants or their powders / resins or household detergents come into contact with the skin of children).

A form of irritative contact dermatitis typical of children in the first months of life is “diaper rash”, induced by the irritating action of urine and feces, aggravated by the constant presence of diapers.

Causes of dermatitis

DIC is a local skin reaction not related to allergic reactions. The irritation of the epidermis is determined by the direct damaging action exerted by toxic substances that penetrate the outer layers of the skin: a phenomenon that is more frequent and marked when the epidermis is characterized by dehydration, desquamation and hypersensitivity or when it is weakened by the alteration of the superficial hydrolipid barrier.

By destabilizing this barrier, excessive washing, cold, wind and excessive exposure to the sun make it more likely that DIC will occur even after contact with the skin of substances that are not particularly aggressive (for example, soaps and detergents in common use, shampoos, deodorants, etc.).

Even some pharmacological therapies (antibiotics, antifungals, anticancer, anti-acne products, etc.) and cosmetics (exfoliating cream, scrubs, anti-aging treatments, etc.) can have a sensitizing effect on the skin, intrinsic or secondary to sun exposure.

Most common symptoms

The most common symptoms of irritant contact dermatitis include:

• redness (erythema)
• burning
• dry skin and peeling
• itching (intense or moderate)
• swelling
• small bubbles, papules or vesicles
• pain of the affected skin area.

In more severe forms of DIC, or if you cannot resist the temptation to rub the skin due to severe irritation and itchy sensation, skin lesions, sometimes bleeding or exuding, and reddish or yellowish crusts may develop.

The extent of skin damage is mainly related to the irritative power of the substance with which the skin comes into contact, its quantity / concentration and the persistence time on the skin. In practice, a very irritating substance can do little damage if it is washed off quickly and completely, while common dishwashing detergents kept in contact with the hands for a long time (without gloves) or rinsed badly at the end of washes, with time, can cause a quite annoying DIC.

Typically, the manifestations are localized only in the skin area that has come into direct contact with the irritant. In most cases, DIC affects the hands and forearms (especially, when the causes of dermatitis are professional), but in reality every part of the body can be involved if a risky compound interacts with the epidermis.

Differential diagnosis

Since the symptoms of “visible” irritant contact dermatitis are very similar to those of atopic eczema and allergic contact dermatitis (DAC), to understand exactly what the origin of the disorder is, an accurate analysis of professional and life habits, any other diseases present and the drugs taken to counteract them are necessary, as well as, often, the execution of targeted skin allergy tests to exclude intolerances.

Specific skin allergy tests are prescribed during an immunological / allergological visit and those normally carried out in the first instance are the Patch tests, which involve the application on the skin of the back of particular patches with small circular areas each containing a different allergen. The patches should be kept in place (without wetting or rubbing) for 72 hours, then they are removed by the doctor who will evaluate the outcome. The appearance of redness at one or more circles indicates the presence of an allergy to the relative compounds, thus confirming the DAC.

Sometimes, the appearance of skin manifestations similar to dermatitis (with variable localization) can also be linked to allergies or intolerances to one or more foods. In these cases, in addition to a very careful examination of dietary habits and the association between intake of certain foods and the appearance of redness, dryness, itching, papules, etc., other allergy tests on blood (Rast test) are generally performed.

Complications

If not addressed correctly from the onset, DIC can cause significant short- and long-term discomfort. In the immediate future, the main complications are related to the persistence of inflammation and alteration of the skin barrier and, in the presence of intense itching, to the lesions that can result from scratching.

All these factors also favor the onset of infections by dermatophyte fungi (mycoses), yeasts (candidiasis) and bacteria. This possibility is signaled by the change in the appearance of the skin affected by DIC, which can become even more inflamed and painful, covered with a whitish patina or produce secretions of various types.

In the long term, the main risk is to see DIC chronically in persistent eczema, very difficult to reverse and potentially disabling, especially when it is localized at the level of the hands.

Treatment

The safest and most effective way to protect yourself from DIC is prevention, which essentially consists of avoiding or, at least, reducing contact with irritants as much as possible (for example, wearing protective gloves and clothing suitable to avoid direct contact when handling hazardous compounds, at work or in the home environment).

Other useful precautions include the thorough, but delicate, washing of the skin areas exposed at the end of the activity at risk (always rinsing thoroughly with fresh water) and the application of specific protective creams, repeated several times a day. Moisturizing and emollient creams specific for sensitive or sensitized skin protect and help restore the integrity of the skin’s hydrolipid barrier, increasing the resistance of the epidermis to irritants.

On the front of pharmacological therapies (however always to be associated with protective and emollient preparations and the removal of the triggering substance), the traditional remedy is represented by corticosteroid-based creams to be applied on the skin area where the symptoms are present. The formulations available on the market are numerous and are able to reduce inflammation, itching and burning after a few days of regular application (provided that you avoid exposing the skin already sensitized to the irritant compound again). For the correct use of these creams it is always advisable to contact your doctor.

In the most severe forms in size or extent of manifestations, it may be necessary to take corticosteroid medications by mouth. In all cases, topical or systemic corticosteroid therapy should be prescribed and monitored by the physician and should be followed for short periods (2-3 weeks maximum), carefully respecting the indicated dosages and frequency of use. During treatment, it is necessary to avoid exposing the skin to the sun because corticosteroids weaken the skin’s natural defenses and increase the risk of pigmentation alterations, erythema and sunburn.

Antihistamines by mouth are not normally indicated against DIC because, as mentioned, it is a form of purely irritative dermatitis, which does not involve allergic reactions involving histamine. On the contrary, they can be useful against DAC, after a first intervention with corticosteroids and together with the removal of the sensitizing allergen, especially to relieve the itchy sensation.

An effective approach to DIC in most common irritative eczema is based on the exclusive use of specific highly moisturizing creams, free of cortisone, much more manageable and better tolerated by both adults and children.

These formulations base their action on the presence of lipids very similar to those naturally present in the epidermis (lamellar lipids), humectants and emollients and panthenol (provitamin B5). The lipid component allows to quickly restore the skin barrier damaged by dermatitis, while panthenol rehydrates the epidermis and, transforming into vitamin B5 after absorption, helps to support the processes of skin cell regeneration.

Thanks to these effects, with the regular application of these specific creams it is possible to reduce dryness, irritation and itching in a few hours and promote the restoration of a stable and efficient epidermal barrier, making the skin more resistant to harmful external agents.

When to consult your doctor

If it is a mild form and the trigger is known (for example, prolonged immersion of the hands in solutions with bleach or aggressive detergents without gloves), DIC can be treated with self-care, applying a specific highly moisturizing and emollient cream, free of cortisone, for a few days. On the contrary, the doctor should always be consulted when the disorder affects fairly large skin areas (over 3-5 cm in diameter) or is characterized by very marked inflammation, especially if associated with vesicles, small cuts or secretions.

In addition, a specialist check is a must if: eczema affects a child or a delicate skin area (face); if the first treatments with moisturizing / reparative creams purchased without a prescription fail to improve the situation after 5-7 days of regular application and removal of the triggering substance; if signs of a possible infection appear (increased inflammation and pain, swelling, presence of secretions or whitish material, macerated skin, etc.).

Even in the case of diaper rash it is advisable to consult the pediatrician before intervening in any way, to have reliable indications and avoid worsening the problem. In general, for mild-moderate diaper rash (which represent the vast majority of cases), to reverse the inflammatory reaction it is sufficient: use super-absorbent diapers and change them often; wash the bottom area carefully but very gently with specific cleansers for the sensitive skin of the child; dry well, dabbing lightly with very soft sponges; apply a highly moisturizing and emollient cream after each wash; Leave the bottom in the air as much as possible to allow the skin to breathe.