> Table of Contents > Dermatitis, Contact
Dermatitis, Contact
Aamir Siddiqi, MD
image BASICS
DESCRIPTION
  • A cutaneous reaction to an external substance
  • Primary irritant dermatitis is due to direct injury of the skin. It affects individuals exposed to specific irritants and generally produces discomfort immediately after exposure (1).
  • Allergic contact dermatitis (ACD) affects only individuals previously sensitized to a substance. It represents a delayed hypersensitivity reaction, requiring several hours for the cascade of cellular immunity to be completed to manifest itself (2).
  • System(s) affected: skin/exocrine
  • Synonym(s): dermatitis venenata
EPIDEMIOLOGY
Common
Incidence
Occupational contact dermatitis: 20.5/100,000 workers/year in one Australian study
Prevalence
  • Contact dermatitis represents >90% of all occupational skin disorders.
  • Predominant sex: male = female
    • Variations due to differences in exposure to offending agents, as well as normal cutaneous variations between males and females (eccrine and sebaceous gland function and hair distribution)
Geriatric Considerations
Increased incidence of irritant dermatitis secondary to skin dryness
Pediatric Considerations
Increased incidence of positive patch testing due to better delayed hypersensitivity reactions (3)
ETIOLOGY AND PATHOPHYSIOLOGY
Hypersensitivity reaction to a substance generating cellular immunity response (4)
  • Plants
    • Urushiol (allergen): poison ivy, poison oak, poison sumac
    • Primary contact: plant (roots/stems/leaves)
    • Secondary contact: clothes/fingernails (not blister fluid)
  • Chemicals
    • Nickel: jewelry, zippers, hooks, and watches (5)
    • Potassium dichromate: tanning agent in leather
    • Paraphenylenediamine: hair dyes, fur dyes, and industrial chemicals
    • Turpentine: cleaning agents, polishes, and waxes
    • Soaps and detergents
  • Topical medicines
    • Neomycin: topical antibiotics
    • Thimerosal (Merthiolate): preservative in topical medications
    • Anesthetics: benzocaine
    • Parabens: preservative in topical medications
    • Formalin: cosmetics, shampoos, and nail enamel
Genetics
Increased frequency of ACD in families with allergies
RISK FACTORS
  • Occupation
  • Hobbies
  • Travel
  • Cosmetics
  • Jewelry
GENERAL PREVENTION
  • Avoid causative agents.
  • Use of protective gloves (with cotton lining) may be helpful.
image DIAGNOSIS
PHYSICAL EXAM
  • Acute
    • Papules, vesicles, bullae with surrounding erythema
    • Crusting and oozing
    • Pruritus
  • Chronic
    • Erythematous base
    • Thickening with lichenification
    • Scaling
    • Fissuring
  • Distribution
    • Where epidermis is thinner (eyelids, genitalia)
    • Areas of contact with offending agent (e.g., nail polish)
    • Palms and soles relatively more resistant, although hand dermatitis is common.
    • Deeper skin folds spared
    • Linear arrays of lesions
    • Lesions with sharp borders and sharp angles are pathognomonic.
  • Well-demarcated area with a papulovesicular rash
DIFFERENTIAL DIAGNOSIS
  • Based on clinical impression
    • Appearance, periodicity, and localization
  • Groups of vesicles
    • Herpes simplex
  • Diffuse bullous or vesicular lesions
    • Bullous pemphigoid
  • Photodistribution
    • Phototoxic/allergic reaction to systemic allergen
  • Eyelids
    • Seborrheic dermatitis
  • Scaly eczematous lesions
    • Atopic dermatitis
    • Nummular eczema
    • Lichen simplex chronicus
    • Stasis dermatitis
    • Xerosis
DIAGNOSTIC TESTS & INTERPRETATION
Diagnostic Procedures/Other
Consider patch tests for suspected allergic trigger (systemic corticosteroids or recent, aggressive use of topical steroids may alter results).
Test Interpretation
  • Intercellular edema
  • Bullae
image TREATMENT
GENERAL MEASURES
  • Remove offending agent:
    • Avoidance
    • Work modification
    • Protective clothing
    • Barrier creams, especially high-lipid content moisturizing creams (e.g., Keri lotion, petrolatum, coconut oil)
  • Topical soaks with cool tap water, Burow solution (1:40 dilution), saline (1 tsp/pt water), or silver nitrate solution
  • Lukewarm water baths
  • Aveeno oatmeal baths
  • Emollients (white petrolatum, Eucerin)
P.285

MEDICATION
First Line
  • Topical medications (6)[A]
    • Lotion of zinc oxide, talc, menthol 0.15% (Gold Bond), phenol 0.5%
    • Corticosteroids for ACD as well as irritant dermatitis
      • High-potency steroids: fluocinonide (Lidex) 0.05% gel, cream, or ointment TID-QID
      • Use high-potency steroids only for a short time, then switch to low- or medium-potency steroid cream or ointment
      • Caution regarding face/skin folds: use lower potency steroids, and avoid prolonged usage. Switch to lower potency topical steroid once the acute phase is resolved.
  • Calamine lotion for symptomatic relief
  • Topical antibiotics for secondary infection (bacitracin, erythromycin)
  • Systemic
    • Antihistamine
      • Hydroxyzine: 25 to 50 mg PO QID, especially useful for itching
      • Diphenhydramine: 25 to 50 mg PO QID
      • Cetirizine 10 mg PO BID-TID
  • Corticosteroids
    • Prednisone: taper starting at 60 to 80 mg/day PO, over 10 to 14 days
    • Used for moderate to severe cases
    • May use burst dose of steroids for up to 5 days
  • Antibiotics for secondary skin infections
    • Dicloxacillin: 250 to 500 mg PO QID for 7 to 10 days
    • Amoxicillin-clavulanate (Augmentin): 500 mg PO BID for 7 to 10 days
    • Erythromycin: 250 mg PO QID in penicillin-allergic patients
    • Trimethoprim-sulfamethoxazole (Bactrim DS): 160 mg/800 mg (1 tablet) PO BID for 7 to 10 days (suspected resistant Staphylococcus aureus)
  • Precautions
    • Antihistamines may cause drowsiness.
    • Prolonged use of potent topical steroids may cause local skin effects (atrophy, stria, telangiectasia).
    • Use tapering dose of oral steroids if using >5 days.
Second Line
Other topical or systemic antibiotics, depending on organisms and sensitivity
Pregnancy Considerations
Usual caution with medications.
ISSUES FOR REFERRAL
May need referral to a dermatologist or allergist if refractory to conventional treatment
COMPLEMENTARY & ALTERNATIVE MEDICINE
The use of complementary and alternative treatment is a supplement and not an alternative to conventional treatment.
Admission Criteria/Initial Stabilization
Rarely needs hospital admission
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Stay active, but avoid overheating.
Patient Monitoring
  • As necessary for recurrence
  • Patch testing for etiology after resolved
DIET
No special diet
PATIENT EDUCATION
  • Avoidance of irritating substance
  • Cleaning of secondary sources (nails, clothes)
  • Fallacy of blister fluid spreading disease
PROGNOSIS
  • Self-limited
  • Benign
REFERENCES
1. Ale IS, Maibacht HA. Diagnostic approach in allergic and irritant contact dermatitis. Expert Rev Clin Immunol. 2010;6(2):291-310.
2. Tan CH, Rasool S, Johnston GA. Contact dermatitis: allergic and irritant. Clin Dermatol. 2014;32(1):116-124.
3. Admani S, Jacob SE. Allergic contact dermatitis in children: review of the past decade. Curr Allergy Asthma Rep. 2014;14(4):421.
4. Martin SF. Contact dermatitis: from pathomechanisms to immunotoxicology. Exp Dermatol. 2012;21(5):382-389.
5. Tuchman M, Silverberg JI, Jacob SE, et al. Nickel contact dermatitis in children. Clin Dermatol. 2015;33(3):320-326.
6. Usatine RP, Riojas M. Diagnosis and management of contact dermatitis. Am Fam Physician. 2010;82(3):249-255.
See Also
&NA;
Algorithm: Rash, Focal
Codes
&NA;
ICD10
  • L25.9 Unspecified contact dermatitis, unspecified cause
  • L23.9 Allergic contact dermatitis, unspecified cause
  • L25.5 Unspecified contact dermatitis due to plants, except food
Clinical Pearls
&NA;
  • Anyone exposed to irritants or allergic substances is predisposed to contact dermatitis, especially in occupations that have high exposure to chemicals.
  • The most common allergens causing contact dermatitis are plants of the Toxicodendron genus (poison ivy, poison oak, poison sumac).
  • Poison-ivy dermatitis typically requires 10 to 14 days of topical or oral steroid therapy to prevent recurrent eruption.
  • The usual treatment for contact dermatitis is avoidance of the allergen or irritating substance and temporary use of topical steroids.
  • A contact dermatitis eruption presents in a nondermatomal geographic fashion due to the skin being in contact with an external source.