Contact dermatitis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at January 28, 2016
StartDiseasesContact dermatitis

Contact dermatitis is a skin irritation or rash. It is caused by either an allergic reaction, or from damaging the protective layer of skin. Skin may become itchy, red or irritated after contact with certain substances such as a new detergent, poison ivy, personal hygiene product or prolonged exposure to water.


Definition & Facts

Contact dermatitis is caused by skin contact with a substance, resulting in a red rash. There may also be blistering, itchiness, and dryness. While it may be uncomfortable, contact dermatitis is not contagious. It is also not lethal.

There are three types of contact dermatitis. Irritant dermatitis is the more common form of contact dermatitis and occurs when skin has direct contact with an irritating substance and damage to the protective layer of skin occurs. Allergic contact dermatitis is when contact with a substance causes an allergic reaction. Photo allergic or photo contact dermatitis is when the skin is sensitive to sun and the substance causing the dermatitis is activated by exposure to sunlight.

Symptoms & Complaints

The severity of the symptoms vary depending on exposure, the strength of the substance and the frequency of exposure to the substance. Reactions to substance exposure may vary and environmental factors such as temperature and sunlight may impact the severity.

Symptoms of irritant contact dermatitis include dry, cracked hands due to prolonged exposure to water; diaper rash; chapped, irritated skin around mouth and lips due to excessive licking; and chemical burns due to contact with cleaning solutions or acids. Examples of allergic contact dermatitis include a red rash, irritated itchy skin, swelling, red bumps or blisters, and tenderness of the skin affected.


Irritant dermatitis is caused by contact with substances such as soaps, detergents, hair dyes, shampoos, rubber gloves, pesticides, acids and other chemicals. The skin reaction may resemble a red skin burn.

Allergic contact dermatitis is caused by contact with a substance that causes an allergic reaction. Common causes are fragrances, nickel or other metals commonly found in jewelry, poison ivy, poison oak, jewelry, nail polish, antibiotics, latex and poison ivy. It can also be triggered by a substance called Balsam of Peru which is in many cosmetics, beauty products and foods.

With allergic reactions, exposure to the substance must have occurred at least one time prior or have had multiple exposures before an immune system response is triggered. Some professions, such as healthcare workers, nurses, doctors, hair stylists, restaurant workers and bartenders have a higher tendency to experience contact dermatitis due to their exposure to multiple chemicals, hand sanitizers and frequent hand washing.

Photo contact dermatitis occurs when the irritating or allergic substance is activated by sunlight. Common substances include sunscreen, shaving lotions and some perfumes. One type of photo contact dermatitis is nicknamed “Margarita dermatitis.” This specific type is caused by a photosensitive compound commonly found in lime and citrus fruit oils in the fruit skin, and celery and parsley for example. When the oil is present on the skin and exposed to sunlight, the rash may occur.

Diagnosis & Tests

In most cases, contact dermatitis does not require professional medical diagnosis such as a lab test. However, distinguishing the type of dermatitis may prove challenging, and a doctor’s physical examination could be useful, especially after avoiding the substance or using topical creams and neither cured the contact dermatitis.

Doctors may perform allergy patch testing. Small patches of possible allergens are applied to the skin and monitored for two days to pinpoint the cause of the dermatitis. Patch testing must be completed by a doctor or qualified provider to ensure results are accurate. It is a useful test for certain patients who have repeated or long-term contact dermatitis occurrences.

If the skin reaction is severe, or signs of infection are present, such as fever and tenderness, one should seek medical attention from a health care provider. If lungs, nasal passages, eyes, mouth or digestive system are painful due to exposure or inhalation of an allergen, one should seek immediate professional medical attention for treatment.

Treatment & Therapy

Avoiding further exposure to the substance will allow the rash to subside. Contact dermatitis rashes generally clear up completely within two to four weeks once exposure to offending substance stops. Washing the affected area with water is recommended to remove traces of the offending substance remaining on the skin. An oatmeal bath may also be soothing to the irritated skin.

Avoiding scratching the affected skin is key. Scratching the skin will irritate it further and prevent healing. Regular application of cool, wet compress cloths to the affected skin may soothe the skin. Applying moisturizers will keep the skin moist, protect and help repair the skin. Oral antihistamines such as diphenhydramine, may relieve itching symptoms. Unless directed by a doctor, one should exercise caution with antihistamine lotion because the lotion may cause further irritation or an allergic reaction.

Doctors may prescribe an oral or topical corticosteroids or an antihistamine if nonprescription strength options are not strong enough. If a prescription is given, it must be finished in its entirety even if the symptoms clear, otherwise the rash may return. Prescriptions can range from three to five days to three or four weeks depending on the severity of the reaction. One should not use additional prescriptions or medicines, or use them more often than directed by the prescribing medical professional.

Prevention & Prophylaxis

Identification of the substance causing the contact dermatitis is key. Once identified, the substance can be avoided or protected against. Once the immune system triggers a response, the substance will be remembered and triggered again with future encounters. The substance should be avoided or protection such as gloves should be used to avoid a contact dermatitis rash recurrence.

If contact with the offending substance occurs at work, a change in work responsibilities may be required. If the offending substance cannot be avoided or protected against in the workplace, a complete job change may be necessary to prevent future contact dermatitis occurrences.