Allergic contact dermatitis and COVID19

Just a moment ago you were delighted to have snatched up one of the last bottles of hygienic hand disinfectant, but today your skin is itching and burning? And your hands are covered with the traces of their endless scratching?

When contact dermatitis affects hand and forearm

You are not alone in this. Contact dermatitis of the hand (medically, “contact dermatitis”) is on the rise worldwide, as a result of the overuse of alcohol-based hand sanitizers in the wake of the Covid19 pandemic. When allergic contact dermatitis affects the hand and forearm, it often manifests itself in endless itching and burning, as described at the beginning.

Allergic contact dermatitis on the rise

A just-published study says that about 75% of medical personnel involved with COVID19 patients in China suffer from contact dermatitis on the hand as a result of hygienic hand disinfection. And in a patient survey in India, about 60% of respondents reported having developed irritant or allergic contact dermatitis on the hand as a result of hygienic hand disinfection due to COVID19.

These results correspond with my personal observations in the professional environment and in my own family: Immediately after the onset of the corona crisis, my husband developed severely itchy complaints on his hands, which have since subsided. And for a few days now, my daughter has been complaining about the excruciating itching caused by allergic contact dermatitis on her hand. (By the way, her hand can be seen in the photo).

What is allergic contact dermatitis?

Contact dermatitis is an inflammation of the skin caused by contact with a certain substance. The principal symptom, a usually very itchy rash, remains confined to the area of contact and usually has clearly defined margins. Although a distinction is made in principle between toxic-irritant and allergic contact dermatitis, the two forms often cannot be clearly distinguished in practice, in view of very similar clinical symptoms in patients with subjectively sensitive skin.

What are the symptoms of allergic contact dermatitis?

The typical symptoms that characterize both forms of contact dermatitis are itching, burning/stinging of the skin or pain when applying creams and other externals. Patients often also describe a feeling of tightness, which may affect larger areas of the skin. When contact dermatitis affects the hand and forearms as a result of hygienic hand disinfection, the inflamed skin areas usually extend from the fingers and especially the knuckles up the back of the hand and into the forearm. Severe symptoms usually also form on the sensitive inner side of the forearm. Allergic contact dermatitis may form areal or patchy erythema and result in dry, rough, and scaly skin. In some patients, wheals and papules have also been observed.

How does allergic contact dermatitis develop?

Allergic contact dermatitis is an immunologically mediated reaction. It does not occur immediately, but only after a certain sensitization phase during which the skin is exposed to the antigen. In practice, this means that contact with a certain ingredient of a skin care or cleansing product is initially tolerated without any problems. After a certain time, often several days but also weeks and even months, sensitization then occurs and the typical symptoms appear. Therefore, it may well be that you were able to perform hygienic hand disinfection for a few days without any problems and without your skin initially showing any negative reactions. However, if the itching, scaling and tautness then suddenly set in, then you almost certainly caught allergic contact dermatitis.

What substances cause allergic contact dermatitis?

The list of antigens that can cause allergic contact dermatitis is long. In a large-scale study, more than 600 ingredients from cosmetics, cleaning products, bath additives and even toothpastes were suspected of causing allergic reactions. In around 10% of cases, these were fragrances, which has since led to their restrictive use in “anti-allergenic” or “fragrance-free” products.

However, it would be wrong to look for the cause of all evil only in “chemistry”. Numerous herbal ingredients such as chamomile, calendula, arnica or sandalwood can also cause allergic reactions in patients with sensitive skin. This is particularly bitter for patients who consciously rely on botanical substances because they perceive them as “natural” and thus less problematic than “chemicals”. Incidentally, the same applies to natural oils that are frequently found in cosmetics, cleaning products and bath additives, such as jojoba oil, tea tree oil or lavender oil.

The toxic contact dermatitis

Toxic contact dermatitis or toxic contact dermatitis does not require an immunological cause and, in particular, does not require a prolonged sensitization phase. The inflammatory reaction of the skin usually occurs immediately, often at the first contact with the irritant. In some manifestations, it may also require repeated contact before inflammatory symptoms appear.

Toxic contact dermatitis is considered the most common form of contact dermatitis. It is estimated to underlie the inflammatory reactions of the skin in 80% of cases. In practice, it is mostly referred to as “sensitive skin” when there is a reaction to certain active ingredients in cosmetics (for example, hydroxy acids, lactic acid, glycolic acid, retinoids) or certain chemicals (for example, calcium thioglycolate, propylene glycol, benzoic acid, and ethanol) in skin care and cleansing products with inflammatory symptoms. Even mild soaps and cleansers can irritate some people’s skin. The list of substances with potentially irritating effects is long and also includes formaldehyde, urea, ammonium derivatives, perubalsam, cinnamic acid derivatives and certain surfactants such as sodium lauryl sulfate, which is found in many hair shampoos.

Allergic contact dermatitis and weather conditions.

Allergic contact dermatitis (like toxic contact dermatitis) may be favored by climatic influences. Cold, dry air contribute to its formation and exacerbation, leading to a more frequent occurrence in winter. Of course, the fact that cold, dry winter air outside or dry warm air in heated rooms anyway puts more strain on the skin surface and damages the protective skin barrier contributes to this. Appropriate care (creams with a high fat content) can prevent this.

What to do against allergic contact dermatitis?

The obvious treatment approach against irritant or allergic contact dermatitis is, of course, primarily to avoid contact with the triggering antigen or at least to keep it to a minimum. In dermatological practice, however, this is easier said than done, because patients often do not know which of their many creams, cosmetics or bath additives could be the cause of the problem. Accordingly, extensive tests are necessary (usually in the form of patch tests) to first identify it.

In our present case of contact dermatitis on the hand, as described at the beginning as a result of frequent hygienic hand disinfection, however, the culprit is quickly identified. It is one of the alcohols used in common products, mostly ethanol or isopropyl alcohol, often both together. In different compositions, they form up to 98% of the ingredients, usually supplemented by a little glycerin, which is supposed to have a refatting effect and thus increase the skin-friendliness of these products.

So the solution is to disinfect your hands less often or to avoid doing so altogether. If you are not in the medical sector, then this should not be a problem for you. This is because alcohol-based hand disinfection is not needed to destroy the corona virus. SARS COV2, as the corona virus is officially called, is a so-called “enveloped virus” and as such is relatively susceptible to external influences. Even mild soap will take care of it without any problems.

Once the allergenic substance is no longer affecting the skin, redness usually subsides within a few days. In the case of scaling, it may take a few weeks. In severe cases, medicinal creams and ointments are also available to relieve itching. For particularly severe allergic contact dermatitis, over-the-counter hydrocortisone or prescription corticosteroid creams may also help, as may antihistamines.

In all cases, your doctor will advise you regarding the best therapy for you. However, it is important to point out once again in conclusion that allergic contact dermatitis can only be avoided in the long term if the irritation caused by the problem substance (here: the hygienic hand disinfectant) is avoided.