AUTHOR INFORMATION

Section 1 of 11

Authored by John A Michael, MD, FRCPC, FAAEM, Consulting Staff, Department of Emergency Medicine, Northshore Medical Center

John A Michael, MD, FRCPC, FAAEM, is a member of the following medical societies: American Academy of Emergency Medicine, College of Physicians and Surgeons of Ontario, Ontario Medical Association, Royal College of Physicians and Surgeons of Canada, and Society for Academic Emergency Medicine

Edited by Mark Louden, MD, FACEP, Consulting Staff, Emergency Department, Duke Health Raleigh Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Mark W Fourre, MD, Program Director, Department of Emergency Medicine, Maine Medical Center, Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Barry Brenner, MD, PhD, FACEP, Professor of Emergency Medicine, Professor of Internal Medicine, and Professor of Anatomy and Neurobiology, Research Director, Department of Emergency Medicine, University of Arkansas for Medical Sciences

Author's Email:	John A Michael, MD, FRCPC, FAAEM
Editor's Email:	Mark Louden, MD, FACEP

eMedicine Journal, April 27 2005, VOLUME 6, Number 4

INTRODUCTION

Section 2 of 11

Background: Contact dermatitis is an inflammatory response of the skin to an antigen or irritant. Contact dermatitis can cause discomfort and embarrassment and is the most common skin condition among workers' compensation claims.

Pathophysiology: The main pathologic feature of contact dermatitis is intercellular edema of the epidermis, which may result in intraepidermal vesicle and bullae formation in acute cases and papules, scaling, and lichenification in chronic cases. Within the dermal layer, various cells congregate around the dilated capillaries to aid in inflammatory response.

Primary irritant dermatitis results from direct injury to the skin. It affects individuals exposed to specific irritants and generally produces discomfort immediately following exposure.

Allergic contact dermatitis (ACD) affects only individuals previously sensitized to the contactant. It represents a delayed hypersensitivity reaction and requires several hours to complete the cascade of cellular immunity before symptoms manifest.

Frequency:

• In the US: Among workers' compensation claims for dermatologic conditions, 90% are for contact dermatitis. The most common antigens are nickel, potassium dichromate, and paraphenylenediamine. Contact dermatitis is the reason for 4-7% of dermatology consults. Hand dermatitis affects 2% of the population at a given time, and 20% of females are affected at least once in their lifetime. Children of persons with contact dermatitis are 60% more likely to have positive patch tests.

• Internationally: Contact allergens are the same in Europe as in the US. However, dermatitis caused by Toxicodendron species is unknown in Europe.

Mortality/Morbidity: Most cases of contact dermatitis are easily treated, but cases with an unrecognized etiology can result in long-term morbidity. In rare cases, epidermal contact with an allergen results in an immunoglobulin E (IgE)-mediated immediate hypersensitivity reaction causing anaphylactic shock. Anaphylactic shock, if untreated, can result in death.

Race: Contact dermatitis is thought to affect whites more frequently than other races. It may be just as common in blacks but more difficult to detect. Fair-skinned redheads are the most vulnerable.

Sex: The female-to-male ratio is 2:1. Women are at highest risk following childbirth.

Age:

• Contact dermatitis is most common during adulthood but affects all ages.

• Irritative contact dermatitis affects very young and very old patients more severely. The most common cause of ACD in elderly patients is topical medication.

• Irritative dermatitis is common in infants. The most common cause is diaper dermatitis.

CLINICAL

Section 3 of 11

History:

• In acute ACD, lesions appear within 24-96 hours of exposure to the allergen.

• The main symptom, in addition to the lesion, is pruritus.

• Location of the dermatitis is helpful in identifying the cause.

• Most heavily contaminated areas break out first, followed by areas of lesser exposure.

• Irritant contact dermatitis is divided into 2 types.

• Mild irritants require prolonged or repeated exposure before inflammation is noted.

• Strong irritants (eg, strong acids, alkalis) can produce immediate reactions similar to thermal burns.

• Photodermatitis is diagnosed by the presence of lesions limited to sun-exposed body areas.

• Burning is the primary complaint in phototoxic reactions.

• Pruritus is the main complaint in photoallergic reactions.

• Contact urticaria reactions occur within 1 hour of exposure to the inciting agent.

• With careful questioning, physicians can identify the cause of most cases of contact dermatitis.

Physical:

• Most cases of contact dermatitis have a similar appearance regardless of the mechanism or cause of inflammation. Inflammatory responses can be categorized into acute, subacute, and chronic phases.

• Acute contact dermatitis presents as clear fluid-filled vesicles or bullae that appear on bright red edematous skin. As the lesions break, skin becomes exudative and weeps clear fluid.

• Subacute contact dermatitis is characterized by less edema and formation of papules.

• Chronic contact dermatitis presents with minimal edema. Scaling, skin fissuring, and lichenification may be noted.

• Contact urticaria has a wheal and flare response at the site of exposure.

Causes: Causes of contact dermatitis are classified into 4 groups according to mechanism of response.

• Allergic contact dermatitis

• A cell-mediated type IV delayed hypersensitivity reaction results from specific antigens penetrating the epidermal skin layer. The antigen combines with a protein mediator and travels to the dermis, where T lymphocytes become sensitized. On the next presentation of the antigen, the allergic reaction takes place.

• Contributing factors include genetics, concentration, duration of exposure, and presence of other skin diseases.

• Most common agents are plants of the Toxicodendron genus (eg, poison ivy, poison oak, poison sumac).

• Other substances include nickel sulfate (various metal alloys), potassium dichromate (cements, household cleaners), formaldehyde, ethylenediamine (dyes, medications), mercaptobenzothiazole (rubbers), thiram (fungicides), and paraphenylenediamine (dyes, photographic chemicals).

• Irritant contact dermatitis

• An irritant produces direct local cytotoxic effect on the cells of the epidermis, with a subsequent inflammatory response in the dermis.

• The most common site is the hand.

• Atopic individuals have an inborn constitutional skin weakness. The risk of developing irritant contact dermatitis is particularly high in individuals with eczema affecting the hands.

• Although irritant contact dermatitis is caused mostly by chemicals (eg, acids, alkalis, solvents, oxidants), plants (eg, hot peppers, garlic, tobacco) also have been implicated.

• Severity of the reaction is related to the amount and duration of exposure to the irritant.

• Photodermatitis

• Irradiation of certain substances by ultraviolet light results in the transformation of the substance into allergens (photoallergic) or irritants (phototoxic).

• Medications (particularly sulfa drugs, thiazides, tetracycline) have been implicated.

• Many plant families are known to cause a phototoxic response. These plant families include citrus, mulberry (figs), and Umbelliferae (parsnip, celery).

• Contact urticaria (immunologic, nonimmunologic)

• Immunologic reaction is a type I IgE-mediated process caused by the immediate release of inflammatory mediators, resulting in a wheal-and-flare reaction. In rare cases, anaphylactic shock can result. Foodstuffs and latex have been implicated.

• Nonimmunologic contact urticaria results in local edema and erythema. It is more common than the immunologic mechanism. Substances containing benzoic, sorbic, cinnamic, or nicotinic acids often are the cause.

DIFFERENTIALS

Section 4 of 11

Bites, Insects
Dermatitis, Atopic
Dermatitis, Exfoliative
Erysipelas
Erythema Multiforme
Herpes Simplex
Herpes Zoster
Herpetic Whitlow
Impetigo
Psoriasis
Scabies
Vulvovaginitis

Other Problems to be Considered:

Nummular eczema
Lichen simplex chronicus
Stasis dermatitis
Xerosis

WORKUP

Section 5 of 11

Lab Studies:

• No ED laboratory studies are of value in diagnosing contact dermatitis.

Other Tests:

• Patch testing may be beneficial to identify the contact allergen and is usually performed in an outpatient setting.

Procedures:

• Biopsy: Pathologic findings include intercellular edema and bullae.

TREATMENT

Section 6 of 11

Emergency Department Care:

• General measures

• Removal of offending agent

• Topical soaks with cool tap water, Burow solution (1:40 dilution), saline (1 tsp/pint), or silver nitrate solution (25.5%)

• Lukewarm water baths (antipruritic)

• Aveeno (oatmeal) baths

• Emollients (eg, white petrolatum, Eucerin) may benefit chronic cases.

Consultations: Patients with recurrent episodes of contact dermatitis or a skin rash of unclear etiology may benefit from an outpatient dermatologic consultation.

MEDICATION

Section 7 of 11

Treatment of contact dermatitis depends on the type, extent, and area of skin lesions on initial presentation. Preventative advice is as important as the prescription of medications. Once an allergen or irritant is identified as the cause of contact dermatitis, eliminate further exposure.

Drug Category: Wet compresses with an astringent -- These are soothing, have a mild antipruritic effect, and keep affected areas clean.

Drug Name	Aluminum acetate (Burow solution) -- Dissolve aluminum acetate tabs in water for a 1:40 solution.
Adult Dose	Apply as compress for 20-30 min 4-6 times/d
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity
Interactions	None reported
Pregnancy	A - Safe in pregnancy
Precautions	For external use only

Drug Category: Topical steroids -- Use ointments on dry or cracked skin and creams on inflamed or weeping lesions.

Drug Name	Triamcinolone acetate (Aristocort) -- Treats inflammatory dermatosis responsive to steroids. Decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing capillary permeability. A moderate potency is available in both ointment (0.1%) and cream (0.5%).
Adult Dose	Apply tid initially; reduce as lesions remit
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; fungal, viral, and bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Multiple complications (eg, severe infections, hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression) may occur; abrupt discontinuation of glucocorticoids may cause adrenal crisis

Drug Name	Hydrocortisone valerate 0.2% (LactiCare HC, DermaGel, Cortaid, Dermacort) -- Lower-potency cream useful on the face. An adrenocorticosteroid derivative suitable for application to skin or external mucous membranes. Has mineralocorticoid and glucocorticoid effects resulting in anti-inflammatory activity.
Adult Dose	Apply tid initially; reduce as lesions remit
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; viral, fungal, and bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Prolonged use, applying over large surface areas, application of potent steroids, and occlusive dressings may increase systemic absorption of corticosteroids and may cause Cushing syndrome, reversible HPA axis suppression, hyperglycemia, and glycosuria

Drug Category: Systemic steroids -- Use in severe cases involving more than 20% of total body surface area (TBSA) or bullae. They have both anti-inflammatory (glucocorticoid) and salt-retaining (mineralocorticoid) properties. Glucocorticoids cause profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.

Drug Name	Prednisone (Deltasone) -- Used for treatment of a variety of diseases, including adrenocortical insufficiency. Prednisone is inactive and must be metabolized to the active metabolite prednisolone. Conversion may be impaired in patients with liver disease. Use for 2-3 weeks with taper. Too short a course results in recurrence of lesions.
Adult Dose	50 mg PO qd for 1 wk; taper by a 10-mg reduction in dose q3d
Pediatric Dose	1 mg/kg PO for 1 wk; taper by a 20% reduction in dose q3d; available in 5 mg/5 mL elixir (prednisolone sodium phosphate); prolonged use in children can suppress growth
Contraindications	Documented hypersensitivity; viral infection, peptic ulcer disease, hepatic dysfunction, connective tissue infections, and fungal or tubercular skin infections; GI disease
Interactions	Coadministration with estrogens may decrease prednisone clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use

Drug Category: Antihistamines -- These agents may be used as adjuncts to relieve pruritus associated with contact dermatitis.

Drug Name	Diphenhydramine (Benadryl) -- Used for the symptomatic relief of allergic symptoms caused by histamine released in response to allergens.
Adult Dose	25-50 mg cap PO q6h prn
Pediatric Dose	5 mg/kg/d (12.5 mg/5 mL elixir) PO divided qid
Contraindications	Documented hypersensitivity; glaucoma; prostatic hypertrophy
Interactions	Potentiates effect of CNS depressants; due to alcohol content, do not give syrup dosage form to patients taking medications that can cause disulfiramlike reactions
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction

Drug Name	Hydroxyzine HCl (Atarax, Vistaril) -- Antagonizes H1 receptors in the periphery and may be used as alternative to diphenhydramine. May also suppress histamine activity in subcortical region of the CNS. Available in 10 mg/5 mL elixir.
Adult Dose	25-50 mg PO tid/qid prn
Pediatric Dose	<6 years: 30-50 mg/d PO divided tid >6 years: 50-100 mg/d PO divided tid
Contraindications	Documented hypersensitivity
Interactions	CNS depression may increase with alcohol or other CNS depressants
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Associated with clinical exacerbations of porphyria (may not be safe for patients with porphyria); ECG abnormalities (alterations in T waves) may occur; may cause drowsiness

Drug Category: Emollients -- These agents may be used as adjuncts to moisturize dry skin in subacute and chronic contact dermatitis.

Drug Name	Urea cream (Ureacin, Ureaphil) -- Promotes hydration and removal of excess keratin in conditions of hyperkeratosis.
Adult Dose	Apply prn to affected area
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; viral skin disease
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Do not use near eyes; caution if applied to broken or swollen skin

Drug Name	Mineral oil (Fleet, Zymenol) -- Promotes removal of excess keratin in conditions of hyperkeratosis.
Adult Dose	Apply prn to affected area
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Observe for hypersensitivity reactions

Drug Category: Barrier creams -- These are the primary agents for diaper dermatitis.

Drug Name	Zinc oxide paste -- Provides relief of minor skin irritations.
Adult Dose	Not established
Pediatric Dose	Apply to affected area, after gentle cleansing and drying, between each diaper change
Contraindications	Documented hypersensitivity
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Observe for hypersensitivity reactions

Drug Category: Dry skin agents -- Moisturize dry skin in subacute and chronic contact dermatitis.

Drug Name	Camphor and menthol (0.5% each) in emollient base (Sarna Anti-Itch) -- Topical drug combination that consists of mild local anesthetics, counterirritants, and antipruritic formulations. Generally safe and effective for symptomatic relief.
Adult Dose	Apply to affected area prn
Pediatric Dose	<12 years: Not established >12 years: Administer as in adults
Contraindications	Documented hypersensitivity
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	For external use only; do not apply to eyes

FOLLOW-UP

Section 8 of 11

In/Out Patient Meds:

• Acute contact dermatitis (mild, moderate)

• Astringents with wet compress

• Topical steroids

• Systemic antipruritics

• Acute ACD with marked edema and bullae (severe) - Above treatment with addition of systemic steroids

• Acute irritative contact dermatitis secondary to strong acids and alkalis (severe) - Prolonged irrigation with water; further treatment same as for burns

• Chronic dermatitis - Topical steroids, emollients, and barrier agents

Deterrence/Prevention:

• Prevention is better than cure.

• The most important part of treatment is to identify and eliminate further exposure to the causative agent.

• Use appropriate protective clothing. Rubber-based products protect against water-based products but not solvents.

Complications:

• Treat secondary bacterial infections with systemic antibiotics.

• Generalized eruption is secondary to autosensitization.

Prognosis:

• Most contact dermatitis resolves without intervention in 4-6 weeks if further exposure is prevented.

• Long-term success in treatment is poor if the physician does not identify the etiology.

Patient Education:

• For excellent patient education resources, visit eMedicine’s Skin, Hair, and Nails Center. Also, see eMedicine’s patient education article Contact Dermatitis.

MISCELLANEOUS

Section 9 of 11

Medical/Legal Pitfalls:

• Failure to diagnose systemic disease or malignancy in elderly patients with unresponsive contact dermatitis.

TEST QUESTIONS

Section 10 of 11

CME Question 1: What is the preferred treatment for an 8-month-old female with a red, scaly, perineal rash with satellite lesions?

A: Mupirocin ointment and triamcinolone cream
B: Triamcinolone cream and clotrimazole cream
C: Zinc oxide paste and clotrimazole cream
D: Triamcinolone cream and zinc oxide paste
E: Mupirocin ointment and zinc oxide paste

The correct answer is C: The infant has an irritative contact dermatitis complicated by a candidal infection that requires treatment with a barrier paste and an antifungal.

CME Question 2: What differential diagnosis should not be considered in a patient who presents with apparent contact dermatitis?

A: Erythema multiforme
B: Erythema migrans
C: Insect bite
D: Impetigo
E: Psoriasis

The correct answer is B: Erythema migrans (Lyme disease) has a more insidious course and a unique progression compared with the other skin lesions listed.

Pearl Question 1 (T/F): The most common causes of allergic Toxicodendron dermatitis in the US are poison ivy, oak, and sumac.

The correct answer is True: Poison ivy, oak, and sumac are the most common causes of allergic dermatitis in the US; dermatitis caused by Toxicodendron species is unknown in Europe.

Pearl Question 2 (T/F): Burning is a more prominent symptom in allergic contact dermatitis and photodermatitis than in irritative dermatitis.

The correct answer is False: Pruritus is the more prominent symptom in all dermatitis except irritative dermatitis, where burning is the most prominent symptom.

Pearl Question 3 (T/F): Allergic contact urticaria is the type of contact dermatitis that may lead to death if untreated.

The correct answer is True: Allergic contact urticaria can develop into full anaphylactic shock.

Pearl Question 4 (T/F): Occult malignancy or serious systemic disease should be considered in an elderly patient with dermatitis unresponsive to treatment.

The correct answer is True: Occult malignancy or serious systemic disease should be considered. Failure to diagnose such is a medical/legal pitfall.

BIBLIOGRAPHY

Section 11 of 11

• Arndt KA: Archives of Dermatology. Second century. Arch Dermatol 1984 Jan; 120(1): 42-3[Medline].
• Cahill J, Keegel T, Dharmage S, et al: Prognosis of contact dermatitis in epoxy resin workers. Contact Dermatitis 2005 Mar; 52(3): 147-53[Medline].
• Champion RH, Burton JL, Ebling FJG: Contact dermatitis. In: Textbook of Dermatology. Boston: Blackwell Science, Inc; 1992: 611-17.
• Ferrera PC, Dupree ML, Verdile VP: Dermatologic problems encountered in the emergency department. Am J Emerg Med 1996 Oct; 14(6): 588-601[Medline].
• Juckett G: Plant dermatitis. Possible culprits go far beyond poison ivy. Postgrad Med 1996 Sep; 100(3): 159-63, 167-71[Medline].
• Kashani MN, Gorouhi F, Behnia F, et al: Allergic contact dermatitis in Iran. Contact Dermatitis 2005 Mar; 52(3): 154-8[Medline].
• Klaus MV, Wieselthier JS: Contact dermatitis. Am Fam Physician 1993 Sep 15; 48(4): 629-32[Medline].
• Rielschel RL, Fowler JF: The role of age, sex, and color of skin in contact dermatitis. In: Contact Dermatitis. Baltimore: Lippincott Williams & Wilkins; 1995: 41-65.
• Shaw S: Managing contact dermatitis. Practitioner 1996 Jan; 240(1558): 16-24[Medline].
• Smit HA, Coenraads PJ: Epidemiology of contact dermatitis. Monogr Allergy 1993; 31: 29-48[Medline].

eMedicine Journals > Emergency Medicine > Dermatology > Dermatitis, Contact

Please email us with any comments you have on our new chapter format.

Author Information | Introduction | Clinical | Differentials | Workup | Treatment | Medication | Follow-up | Miscellaneous | Test Questions | Bibliography