Dermatological Allergology | Specialists and Information

The skin is the human body’s largest organ and performs numerous sensory and tactile functions.

Through specialized sensory cells in the skin, we can perceive heat and pain and convey tactile stimuli.

In addition, the skin performs important protective functions: As a barrier, it separates the body from the environment, prevents dehydration, and blocks the entry of foreign substances.

The skin recognizes even microorganisms as pathogens and fights them off. It provides protection against UV radiation through melanin pigmentation and body hair, as well as against mechanical stress.

The skin regulates body temperature. This thermoregulation occurs through blood circulation (blood vessels) and sweat production.

As an outer barrier, the skin is well-equipped to withstand external environmental influences and pathogens thanks to its structure and function.

Only when the skin’s protective functions are disrupted do problems and diseases arise, such as:

• Infections
• Allergies, or
• Skin damage such as sunburn

Stronger or prolonged exposure to UV rays or chemicals can lead to dangerous conditions such as skin tumors.

Even though the skin has an effective self-protective function, our modern lifestyle puts it under strain.

These include frequent cleansing with harsh surfactants (detergents) and strong or prolonged sun exposure.

That’s why it’s important to give your skin the protection it needs, such as:

• Wearing appropriate (protective) clothing
• Applying UV or sunscreen
• Preventing injuries
• Avoiding harmful substances

The skin consists of three layers: the epidermis, dermis, and subcutaneous tissue @ bilderzwerg /AdobeStock

Over time, the immune system learns to distinguish between the following substances:

• Foreign substances that cause illness
• Substances to which it must develop a tolerance, such as pollen

During an allergic reaction, the immune system reacts to a specific substance (allergen). The immune system recognizes the substance as foreign based on its specific surface structure.

Simply put, allergens can be chemical, plant-based, or animal-derived substances. The immune system uses certain characteristics to determine whether these substances should be fought off or not.

An allergy involves either an overreaction to foreign substances that have entered the body. In this case, the immune system has not properly developed tolerance.

The following substances can trigger an allergic reaction:

• Cleaning products
• Cosmetics
• Hair dyes
• Preservatives
• Pollen
• Animal toxins and
• Medications

Red, dark, or pale patches, itching, and swelling may indicate a skin allergy @ Pormezz /AdobeStock

Allergic reactions can be classified into four types depending on the immune response. 

The relevant types of skin allergies are:

• Immediate-type allergy (Type I) and
• Delayed-type (Type IV) in the case of contact allergy

When contact with such substances causes a pathological change on the skin, experts refer to it as a skin allergy.

However, an allergic reaction is not necessarily limited to the skin. Depending on how an antigen enters the body (skin, bloodstream, lungs, eyes), the reactions may be localized. In such cases, experts refer to a contact allergy. 

In extreme cases, they can also affect the entire body and trigger life-threatening reactions (anaphylactic shock following a bee sting).

Contact allergies occur in two phases: During the sensitization phase, initial contact with the allergen takes place to sensitize certain immune cells to the substance.

Upon repeated contact with the same allergen, the previously sensitized cells are activated, triggering an inflammatory reaction. 

This type of contact dermatitis results in typical skin reactions such as redness, itching, swelling, or scaling.

Substances that most commonly trigger contact allergies (so-called contact allergens) include: 

• Nickel sulfate (found in: fasteners, cutlery, medical instruments, furniture, bleach, paint glazes, jewelry, clothing)
• Cobalt chloride (Found in: same as nickel sulfate)
• Ingredients in cosmetics, cleaning products, food, and industrial fluids
• Rosin (found in: paper, bandages, polishes, depilatories, sports waxes) 

Contact allergies occur in all age groups and are very common in Germany. 

If you suspect you have a skin allergy, the right person to consult is a dermatologist who has completed additional training in “allergology.” 

However, ENT specialists, pulmonologists, pediatricians, and other medical specialists can also complete this additional training in “allergology.” 

They specialize in the diagnosis and treatment of allergic diseases.

After successfully completing this advanced training, these physicians are able, among other things, to:

• Conduct allergy tests and interpret the results accurately.
• Provide recommendations regarding diet and allergy prevention, etc.
• Administer specific immunotherapy (hyposensitization)
• To provide emergency treatment for anaphylactic shock

The diagnostic process begins with a detailed medical history: During a consultation, the allergist records the patient’s medical history.

This includes:

• Previous illnesses
• Symptoms and when they occur
• Medications taken
• Exposure to certain substances 

During the physical examination, the doctor will closely examine any skin changes. If necessary, he or she may also take a histological sample for laboratory analysis. This often allows the doctor to identify the likely trigger of a (contact) allergic reaction.

There are various skin tests that can further identify the allergen (allergy test).

This helps distinguish between a contact allergy (Type IV sensitization) and a Type I sensitization. 

Depending on the patient’s medical history, the doctor selects a specific testing method. The doctor diagnoses a contact allergy using a patch test.

In this test, the doctor applies the suspected allergens to small areas of skin under standardized conditions to observe the skin’s reaction. 

Type I sensitization can be detected using other methods, such as:

• rub test 
• Prick test, or 
• Intradermal tests with immediate and delayed readings (immediate-type allergy versus delayed-type allergy)
• Atopy patch test (“patch test”) and 
• Determination of specific IgE antibodies against allergens in serum (laboratory test) 

If certain preliminary tests are not conclusive enough, a provocation test is performed. 

In a provocation test, the patient inhales the suspected allergen (bronchial or inhalation provocation test). It is also possible to apply the allergen to the nasal mucosa (nasal provocation test), the conjunctiva (conjunctival provocation test), or to administer it orally (oral provocation test).

The test is also performed under standardized conditions and, depending on the symptoms, in emergency departments and, if necessary, in specialized clinics. The physical reaction indicates whether or not an allergy to a specific substance is present.

Skin tests are quite reliable for detecting sensitization to pollen or house dust mites.

Atopic dermatitis, also known as atopic eczema, is not an allergy in the sense described above. 

Like asthma, allergic rhinitis, and conjunctivitis (including hay fever and house dust mite allergy), it is one of the three conditions in the atopic spectrum.

These conditions involve a physical reaction to triggering substances. The three conditions can occur one after the other or simultaneously.

Neurodermatitis manifests as a skin rash, eczema, and severe itching. The exact causes remain unclear to this day. A genetic predisposition is suspected.

An enzyme defect leads to a disruption of the skin’s barrier function, accompanied by water loss. This allows allergens and irritants to penetrate the skin more easily and cause damage. 

Atopic dermatitis is the most common chronic skin condition, affecting 0 to 15% of children and 2.5 to 3.5% of adults @ isavira /AdobeStock

The risk of developing an allergy can be reduced during the period from late pregnancy through the baby’s first few months of life.

Diet plays an important role even in early childhood. Nutrition experts recommend a varied diet and regular consumption of fatty fish, as the unsaturated fatty acids they contain help prevent allergies. 

The guidelines for allergy prevention, for example, include the following recommendations: 

• Babies over 4 months of age should be fed exclusively breast milk. 
• Avoid being overweight 
• Regular consumption of fish during pregnancy and while breastfeeding, as well as in complementary foods
• Avoid air pollutants and tobacco smoke
• Avoid indoor environments that promote mold growth
• Vaccinations according to the recommendations of the Standing Committee on Vaccination (STIKO) 
• The introduction of complementary foods should not be delayed. 
• No cats in households with at-risk children; keeping dogs in the household, however, is not a problem

Prebiotics appear to have a preventive effect on atopic eczema. The consumption of vegetables, fruits (Mediterranean diet), and milk fat also appears to have a preventive effect on atopic diseases

The best allergy prevention is thorough education by qualified physicians. Preventive health protection also includes the home environment. 

Exposure to airborne pollutants and mold should be avoided as much as possible. A varied diet rich in fresh fruits and vegetables reduces the risk of future allergies even during pregnancy.