Contact dermatitis

What is contact dermatitis?

Contact Dermatitis is an acute or chronic dermatitis that results from direct skin contact with chemicals or allergens.
These agents could be Chemicals, Animal or plant products, Physical agents like heat, cold, ultraviolet rays or ionizing radiation.

Classification of Contact dermatitis

Contact dermatitis is classified as:

  1. Irritant dermatitis
  2. Acute irritant dermatitis,
  3. Cumulative insult dermatitis
  4. Allergic contact dermatitis
  5. Phototoxic dermatitis
  6. Photo-allergic dermatitis

Symptoms and clinical features of contact dermatitis

1. Acute phase

  • Tiny vesicles, weepy and crusted lesions

2. Resolving or chronic contact dermatitis

  • Scaling, erythema, and possibly thickened (lichenified) skin
  • Itching, burning, and stinging may be severe

Contact dermatitis is recognized by the
distribution and configuration of the lesion which usually corresponds to the contactant e.g.

  1. Face: cosmetics
  2. Photodermatitis: airborne allergens e.g. dust, fumes, sprays
  3. Neck: nickel necklace, perfume, and collars of garments
  4. Hands: various chemicals handled at home, at work and at leisure hours
  5. Feet: shoes, socks, remedies for athletes’ foot, etc

Differential diagnoses

  • Atopic dermatitis
  • Seborrhoeic dermatitis.
  • Psoriasis
  • Dermatophyte infection
  • Lichen planus
  • Face: lupus erythematosus, pellagra, rosacea

Complications of contact dermatitis

  1. Impetiginization
  2. Secondary dissemination

Investigations

  • Patch test
  • Occupational site assessment

Treatment for contact dermatitis

Treatment objectives

  1. Cure the dermatitis.
  2. Identify cause(s) and avoid further contact

Drug treatment

As for atopic dermatitis

Supportive measures

  • Counselling (after identifying the cause)
  • Allergen replacement