Clinical Handbook of Contact Dermatitis

Diagnosis and Management by Body Region

Robin Lewallen, Adele Clark, Steven R. Feldman, Robin Lewallen, Adele Clark, Steven R. Feldman

• Publisher: CRC Press
• Year: 2014
• Print ISBN: 9781138416659
• eBook ISBN: 9780429586194
• Edition: 1
• Topic: Medicine
• Subtopic: Dermatology

The Clinical Handbook of Contact Dermatitis: Diagnosis and Management by Body Region uses a succinct approach to help clinicians manage this multifaceted condition. Organized by body region, the handbook presents the most common allergens and irritants for a given location. It discusses products containing common allergens and irritants such as top

CHAPTER 1

Introduction to contact dermatitis

Robin Lewallen and Steven R. Feldman

Contact dermatitis is a common skin condition frequently seen by physicians. It affects approximately 20% of people in the United States. It is responsible for 70 to 80% of all reported occupational skin diseases, and it is a frequent chief complaint of clinic visits.¹ There are two main types of contact dermatitis: irritant contact dermatitis and allergic contact dermatitis. Irritant contact dermatitis (ICD) is far more frequent than allergic contact dermatitis (ACD). While the clinical appearance may be similar, allergic contact dermatitis differs from irritant dermatitis in many ways (Table 1.1).

Table 1.1 – Allergic versus irritant contact dermatitis

	Allergic contact dermatitis	Irritant contact dermatitis
Definition	An acquired inflammatory response to an allergen that occurs only in individuals who have been sensitized to the allergen	A nonspecific immune reaction of the skin to a substance that results in a skin eruption in any individual exposed to a high enough concentration
Molecular mechanism	Cell-mediated hypersensitivity through Langerhans cells and CD4+ T cells after contact with a specific allergen (delayed Type IV hypersensitivity reaction)	Skin barrier disruption and cellular damage of the keratinocyte membrane from contact when an irritant activates the innate immune system
Time between exposure and cutaneous manifestation	Hours to days	Within minutes to several hours
Body location	Scalp is uncommon	Hands and face are common
Symptoms	Itching	Pain and burning
Factors that alter severity of reaction	Concentration of allergen and length of exposure Atopic patients are reported to be less likely to have ACD	Dry skin and thicker skin reacts less severely Atopic patients react more severely due to reduced barrier function
Common allergens/irritants	Top 10 allergens from patch test results^2: nickel sulfate, balsam of Peru (Myroxylon pereirae), fragrance mix, quaternium-15, neomycin sulfate, bacitracin, formaldehyde, cobalt chloride, methyldibromo glutaronitrile, and p-phenylenediamine	Top irritants^3,4: low humidity, heat, water, detergents, solvents, oils, heat and sweating, dust and fibers, acids, and alkalis
Histology	Acute: epidermal spongiosis with superficial dermal edema, eosinophils, and mild perivascular lymphocytic infiltrate in the upper dermis; vesicles can contain neutrophils Chronic: psoriasiform changes	Varies depending on the severity and chronicity of exposure Low concentrations: mimics acute ACD High concentrations: epidermal necrosis, which can be full thickness with balloon degeneration
Testing	Patch test Photopatch test Provocative use test	None

The list of allergens that cause ACD continues to grow. There are over 3,500 environmental contact allergens reported in the literature.⁵ Exposure to a particular allergen can occur for years before developing a delayed hypersensitivity immune response. After sensitization occurs, subsequent exposure to the allergen may result in ACD even if used in small concentrations.⁶ Poison ivy (urushiol) is another common allergen but is not included in typical testing or in the frequency results by the North American Contact Dermatitis Group (NACDG). Topical medications are a common cause of contact dermatitis, including antibiotics (58%), corticosteroids (30%), and anesthetics (6%). This generates a conundrum when selecting treatments for contact dermatitis, as upwards of 30% of patients with a medication allergy had a positive patch test to a topical corticosteroid, either the steroid or the vehicle.⁷ Many of the products that are used on a daily basis contain one or more potential allergens (Table 1.2).

While ACD is a specific reaction to an allergen that occurs only in sensitized individuals, ICD can occur in anyone exposed to an irritant at a high concentration or for a significant length of time. There are many substances that can disrupt the skin’s barrier and activate the innate immune response. Occupational dermatitis, which is in large part caused by irritant dermatitis, costs up to $1 billion annually from medical bills, medications, worker’s compensation, and lost work hours.⁸

Table 1.2 – Products containing common allergens

Product	Allergen
Metals	Nickel, cobalt, sodium gold thiosulfate, potassium dichromate
Fragrance	Balsam of Peru (Myroxylon pereirae), ylang-ylang oil, jasmine Fragrance mix I (cinnamic aldehyde, cinnamyl alcohol, hydroxycitronellal, isoeugenol, eugenol, oak moss absolute, α-amyl cinnamic aldehyde, geraniol) Fragrance mix II (Lyral®, citral, farnesol, citronellol, hexyl cinnamic aldehyde, coumarin)
Rubber accelerators and latex	Carba mix, mercaptobenzothiazole (MBT), thiuram mix, mercapto mix, black rubber mi...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Acknowledgments
• Chapter 1 Introduction to contact dermatitis
• Chapter 2 Scalp
• Chapter 3 Face
• Chapter 4 Eyelids
• Chapter 5 Mouth, lips, and perioral region
• Chapter 6 Neck
• Chapter 7 Hands
• Chapter 8 Extremities
• Chapter 9 Feet
• Chapter 10 Trunk
• Chapter 11 Anogenital region
• Chapter 12 Patch testing
• Chapter 13 Treatment considerations
• Quick Reference
• Index