What are the symptoms, causes, and treatment for contact dermatitis?

Contact Dermatitis: Symptoms, Causes, and Treatment

Contact dermatitis is effectively managed through allergen/irritant identification and avoidance, skin barrier repair with moisturizers, and inflammation control using topical corticosteroids. 1

Symptoms

• Contact dermatitis presents with erythema, scaling, and visible borders, often with intense itching and discomfort 2
• Acute cases may involve dramatic flares with erythema, vesicles, and bullae, while chronic cases may present with lichenification, cracks, and fissures 2
• In the acute phase, contact dermatitis is characterized by erythema and vesiculation, while the chronic phase typically shows dryness, lichenification, and fissuring 3
• Symptoms may improve during weekends and holidays (for occupational exposures) and worsen upon return to work 3

Types and Causes

Irritant Contact Dermatitis

• Occurs following exposure to irritating substances without immune system involvement 3
• Common causes include detergents, organic solvents, soaps, weak acids, alkalis, and frequent hand washing 3
• Can be acute (from single overwhelming exposure to strong irritants) or chronic/cumulative (from repetitive exposure to weaker irritants) 3
• "Wet" irritants include detergents and solvents, while "dry" irritants include low-humidity air, heat, and dusts 3

Allergic Contact Dermatitis

• Involves sensitization of the immune system to specific allergens, resulting in a delayed hypersensitivity reaction 3, 2
• Common allergens include poison ivy/oak/sumac, nickel, fragrances, cobalt, and p-phenylenediamine (PPD) 3, 2
• Prevalence of contact allergy to specific allergens in the European general population ranges between 10% and 27% 3

Other Types

• Subjective irritancy: idiosyncratic stinging reactions within minutes of contact, usually on the face 3
• Phototoxic, photoallergic, and photoaggravated contact dermatitis 3
• Systemic contact dermatitis: occurs after systemic administration of allergens 3

Diagnosis

• Clinical features alone are unreliable in distinguishing allergic contact from irritant and endogenous dermatitis, particularly with hand and facial dermatitis 3
• A detailed history should include:
  • Initial location of symptoms and spread pattern 3
  • Relationship to specific products or activities 3
  • Occupational and recreational exposures 3
  • Personal or family history of atopy 3
• Patch testing is recommended for persistent eczematous eruptions to identify specific allergens 3
• Additional readings at day 6 or 7 should be considered if results are unexpectedly negative at day 4 3

Treatment

General Approach

• Identify and completely avoid the causative agent (allergen or irritant) 1, 4
• Restore the skin barrier and reduce inflammation through multiple treatments 4

Specific Treatments

Topical Treatments

• Topical corticosteroids are the mainstay treatment for established contact dermatitis 3

  • For localized acute allergic contact dermatitis, mid- or high-potency topical steroids like triamcinolone 0.1% or clobetasol 0.05% are effective 2
  • Over-the-counter hydrocortisone can be applied to affected areas not more than 3-4 times daily for adults and children over 2 years of age 5
  • Do not use hydrocortisone for more than 7 days unless directed by a doctor 5

• Moisturizers and emollients

  • Apply immediately after washing hands to repair skin barrier 1
  • Use moisturizers packaged in tubes rather than jars to prevent contamination 1
  • Apply two fingertip units of moisturizer to hands after washing 1

• Soap substitutes and gentle cleansers help prevent further irritation 1

• Topical tacrolimus should be considered where topical steroids are unsuitable or ineffective 3

Systemic Treatments

• For extensive allergic contact dermatitis (>20% of skin area), systemic steroid therapy is often required and offers relief within 12-24 hours 2
• For severe poison ivy/oak/sumac dermatitis (rhus dermatitis), oral prednisone should be tapered over 2-3 weeks to prevent rebound dermatitis 2
• Second-line treatments for steroid-resistant chronic hand dermatitis include:
  • PUVA (psoralen plus UVA) therapy 3
  • Alitretinoin for severe chronic hand eczema 3
  • Immunosuppressants such as azathioprine and ciclosporin 3, 1

Protective Measures

• Use appropriate gloves with cotton liners for household tasks 1
• Remove gloves regularly and apply moisturizer before wearing gloves 1
• Consider skin care and skin protection creams in preventing occupational dermatitis 3
• After-work creams show benefit in reducing irritant contact dermatitis 3
• Barrier creams alone have questionable value and may give a false sense of security 3, 1

Special Considerations

• For poison ivy/oak/sumac exposure, wash the area with soap and water or a commercial decontamination product as soon as possible 3
• Cool compresses and oatmeal baths may provide symptomatic relief for poison ivy/oak/sumac exposure 3
• Workplace assessment may be necessary for occupational dermatitis to identify all potential hazards 1
• Nickel-sensitive patients may benefit from low-nickel diets in some cases 3, 1

Prognosis

• Long-term prognosis for occupational contact dermatitis is often poor 3
• Only 25% of patients with occupational contact dermatitis completely heal; 50% have periodic symptoms and 25% have permanent symptoms 3
• Prognosis for milder cases depends on the ease of allergen/irritant avoidance 3
• If the patient can completely avoid the cause, dermatitis will typically clear 3