24.3 Types of Dermatitis

Pathophysiology

Contact dermatitis begins when an allergen contacts the skin. Once the allergen has entered the stratum corneum, it is obtained by Langerhans cells. The antigens then undergo processing by these cells and are visible on their surfaces. Subsequently, the Langerhans cells move toward local lymph nodes, where the antigens encounter neighboring T lymphocytes for destruction. These lymphocytes may then migrate within the blood and into the epidermis. This process is collectively known as the sensitization phase of contact dermatitis. The elicitation phase occurs after re-exposure takes place. A cytokine-induced proliferation process is triggered when Langerhans cells that include the relevant antigen correspond with the antigen-specific T lymphocytes for that antigen. This proliferation produces a localized, inflammatory response (Murphy et al., 2022).

Pathophysiology

Since this type of dermatitis belongs to the atopy family, there is a genetic tendency to develop allergic diseases associated with a heightened immune response, like asthma, eczema, and allergic rhinitis. The pathophysiology of this type of dermatitis is multifactorial and complex. The factors include alterations in cell-mediated immune responses, environmental factors, and IgE-mediated hypersensitivity. A key factor for atopic dermatitis is the presence of a loss-of-function mutation in the gene for the filaggrin protein. This can lead to severe atopic dermatitis due to a potential increase in trans-epidermal water loss, dehydration, and pH alterations. Those with eczema usually have a higher pH level than those that do not have eczema and can cause the skin barrier to not function as it should. Other genetic changes that may contribute to atopic dermatitis are an imbalance of Th2 to Th1 cytokines, which creates alterations in cell-mediated immune responses and can promote IgE-mediated hypersensitivity. Also, pH alterations lead to changes in enzyme activity which can trigger inflammation. In addition to loss-of-function mutations of filaggrin, harsh detergents, fragrances, and preservatives can alter pH levels of the skin (Kim et al., 2019).

Clinical Manifestations of Atopic Dermatitis

This type of eczema is characterized by itchy, chronic inflammation of the upper skin layers, as shown in Figure 24.5. In the acute phase, the rash may be red, oozing, and have crusted areas with occasional blisters present. The chronic phase may have dry, thickened areas. The rash may occur in one or more areas in adults and can spread to several areas on infants. The rash can vary in intensity, color, and location, but it is always itchy, which triggers scratching that ultimately makes the problem worse. Stress, irritation, and dry air can increase itchiness. Environmental triggers include harsh soaps, excessive bathing or hand washing, sweating, rough fabrics, wool, or Staphylococcus aureus present on the skin. Allergens like wheat, dairy, and eggs may also be a trigger for this reaction. Tears in the skin caused by scratching or rubbing can often lead to bacterial infections.

Figure 24.5 This person is using an ointment to treat their chronic eczema. (credit: “Applying steroid ointment to eczema – hand” by Kate Whitley/Welcome Collection, CC BY 4.0)

Pathophysiology

Dermatitis medicamentosa is a hypersensitivity manifestation of IgE-dependent (immunologic) or T cell–mediated (nonimmunologic) mechanisms initiated by topical, oral, or parenteral drug administration. Immunologic responses happen when specific antibodies or explicitly sensitized lymphocytes to a drug develop during the sensitization period, which can be up to 4 or 5 days after initial exposure.

Nonimmunologic responses may be caused by a variety of factors, including collective buildup of a drug; individual genetic predisposition; pharmacologic action of a drug; drug sensitization of the skin, producing a reaction with exposure to ultraviolet light; increased sensitivity to irritating topical solutions; and individual immune status (Knee & Sandberg-Cook, 2016).

Diagnostics and Laboratory Values

Patch testing is indicated when the inflammation is not resolved with avoidance therapy. The patch test uses the Thin-layer Rapid Use Epicutaneous (T.R.U.E.) test. This test typically contains thirty-six allergens that are applied to the skin and then interpreted by a health care provider. Other patch testing options are available and may be applied using adhesive patches that contain small amounts of an allergen. The standard procedure for patch testing is to apply the patches to the skin on the back. The area is assessed for presence of edema, erythema, vesicles, crusts, and the size of the reaction in order to determine a positive or negative reaction. Patch testing is contraindicated with widespread, acute dermatitis. Other diagnostic testing may show elevated serum IgE and eosinophil levels.

Recognizing and Analyzing Cues

As part of recognizing and analyzing cues, the nurse should conduct a physical examination and complete the patient’s personal and family history of allergies. Physical examination findings may reveal any of the clinical manifestations described previously. The nursing assessment should also include the patient’s exposure risks in order to attempt to identify the irritant. The patient may be exposed to irritants at work, during leisure activities, or at home. Irritants may include chemical solvents, detergents, soaps, lotions, cosmetic products, or any other substance that may come in contact with the skin.

Prioritizing Hypotheses, Generating Solutions, and Taking Action

After documenting findings from the examination and history, the nurse should verify orders received from the provider. Interventions may be aimed at improving symptoms, administering medications, educating the patient about avoidance therapy, and promoting home-based care. Nursing interventions for improving symptoms may include administering medications and eliminating identified or suspected irritants causing dermatitis. Medications may include topical corticosteroids for milder cases, oral antihistamines to relieve pruritus, system corticosteroids, topical hydrophilic creams or petrolatum to soothe the skin, and antibiotics for infection. Other interventions may include cool compresses or the application of aluminum acetate, which may be used to treat inflammation and itching. The nurse should also ensure the patient understands the importance of maintaining their medication or treatment regimen to improve and prevent symptoms. The nurse can help the patient identify barriers to adherence in order to help the patient identify alternative solutions. For example, a patient may not be able to avoid a certain chemical at their work; therefore, the nurse should help the patient identify ways to protect themselves, such as wearing personal protective equipment when handling the chemical. Discharge planning should include steps to educate the patient and family regarding self-care at home, including strategies for ensuring medications are used correctly, treatment schedules are adhered to, and exposure to irritants is minimized. The purpose, procedure, and schedule of any prescribed regimens from the provider should be reinforced to ensure patients and family members all understand. The nurse should review the name, dosage, and frequency of all medications, as well as any side effects from medications or other treatments and actions to take in the event of side effects. Side effects may vary depending on the medication prescribed and have been covered previously in this chapter.

Other nursing interventions may be aimed at ensuring adequate coping with this diagnosis. Skin breakouts may be disturbing or embarrassing and have a negative impact on the patient’s self-esteem. The nurse should ensure the patient understands the purpose of therapies aimed at treating dermatitis and measures that prevent the disorder from appearing. The nurse may also need to help the patient and family identify ways to incorporate care into their lifestyle.

For patients with dermatitis medicamentosa, the known or suspected medication causing the reaction should immediately be discontinued. The patient should also be educated on the need to notify other providers and health-care facilities of the allergy and advised to wear a medical alert bracelet to alert providers in emergent situations when the patient is unable to speak. Since this reaction can have systemic symptoms, the nurse should be aware of the potential for anaphylaxis and have equipment readily available in case of emergency. The nurse should also monitor and treat systemic symptoms per provider orders.

Evaluating Outcomes

The nurse will want to evaluate expected outcomes for patients with allergic dermatitis. The nurse can determine if symptoms have improved based on clinical examination as well as patient verbalization. The nurse can determine that the patient understands the education provided by having the patient verbalize or reiterate the teachings regarding diagnosis, medications, treatment, schedule, home care, and allergen avoidance measures. The patient should also be able to demonstrate how to properly administer their medications and to describe signs and symptoms to report, including anaphylaxis, angioedema, difficulty swallowing, wheezing, difficulty breathing, peripheral tingling, and urticaria.