From the Guidelines
Allergic Contact Dermatitis (ACD) is a type IV hypersensitivity reaction that requires prompt identification and avoidance of the triggering allergen, along with symptomatic treatment, to prevent recurrence and improve quality of life. ACD occurs when the skin comes into contact with an allergen, causing an immune response that leads to inflammation, redness, itching, and sometimes blistering 1. The most common contact allergens include nickel, neomycin, fragrance, formaldehyde, and other preservatives, lanolin, and rubber chemicals 1.
Diagnosis and Treatment
Diagnosis of ACD is by patch testing, whereby suspected allergens are placed on unaffected skin, typically the back, for 48 hours, and the presence of a reaction is assessed at the time of initial patch removal and again at a later time point, up to 7 days after application 1.
- First-line treatment includes topical corticosteroids such as triamcinolone 0.1% or betamethasone 0.05% applied twice daily for 1-2 weeks to reduce inflammation.
- For severe or widespread cases, oral corticosteroids like prednisone may be prescribed, typically starting at 40-60mg daily and tapering over 2-3 weeks.
- Antihistamines such as cetirizine 10mg or diphenhydramine 25-50mg can help control itching.
- Cool compresses and calamine lotion provide symptomatic relief.
- For recalcitrant cases, a stronger topical steroid, phototherapy, systemic therapy, or occupational modification may be necessary 1.
Prevention and Management
Once the specific allergen is identified through patch testing, strict avoidance of the allergen is crucial for preventing recurrence 1. Barrier repair creams containing ceramides help restore skin integrity after the acute phase. ACD differs from irritant contact dermatitis in that it involves a specific immune response to an allergen rather than direct skin damage, which explains why symptoms may appear 48-72 hours after exposure and why previous sensitization is necessary for the reaction to occur. Individuals with suspected ACD should be patch tested to evaluate for a clinically relevant causal allergen, and those with recalcitrant hand dermatitis should seek a dermatology consultation 1.
From the FDA Drug Label
5 Allergic States Control of severe or incapacitating allergic conditions intractable to adequate trials of conventional treatment: ... Contact dermatitis The treatment for Allergic Contact Dermatitis (ACD) includes the use of prednisone for control of severe or incapacitating allergic conditions, including contact dermatitis.
- The main idea is to use prednisone as an adjunctive therapy for short-term administration to tide the patient over an acute episode or exacerbation.
- Key words: Allergic Contact Dermatitis, prednisone, contact dermatitis, allergic states 2
From the Research
Definition of Allergic Contact Dermatitis (ACD)
- Allergic Contact Dermatitis (ACD) is a delayed hypersensitivity reaction that occurs when the skin comes into contact with a foreign substance, leading to skin changes after reexposure to the substance 3.
- It is a common inflammatory skin condition characterized by erythematous and pruritic skin lesions 3.
Causes of ACD
- The most common substances that cause ACD include poison ivy, nickel, and fragrances 3.
- Other substances such as antibiotics, corticosteroids, local anesthetics, and nonsteroidal anti-inflammatory drugs can also cause ACD 4.
Symptoms of ACD
- ACD usually leads to erythema and scaling with visible borders, as well as itching and discomfort 3.
- Acute cases may involve a dramatic flare with erythema, vesicles, and bullae, while chronic cases may involve lichen with cracks and fissures 3.
Treatment of ACD
- Localized acute ACD lesions are successfully treated with mid- or high-potency topical steroids, such as triamcinolone 0.1% or clobetasol 0.05% 3.
- If ACD involves an extensive area of skin (greater than 20 percent), systemic steroid therapy is often required and offers relief within 12 to 24 hours 3.
- Emerging therapies such as biologic drugs (e.g. dupilumab) and small molecule inhibitors (e.g. JAK inhibitors) may also be effective in treating severe ACD 5.
- Avoidance of the suspected irritants or allergens is also crucial in the treatment of ACD, as well as restoring the skin barrier and reducing skin inflammation through multiple treatments such as emollients, topical corticosteroids, and antihistamines 6.
Diagnosis of ACD
- A complete medical history, including occupational history, is very important in the diagnosis of ACD 6.
- Patch testing is a well-known diagnostic test for ACD, but other tests such as photopatch test, skin tests for detecting immediate contact reactions, serum allergen-specific IgE test, and qualitative and quantitative testing of allergen in the suspected materials may also be used 6.
- Hypersensitivity reactions to corticosteroids, which are commonly used to treat ACD, can occur and require careful evaluation and alternative treatment options 7.