Table 1.

Comparison Between Irritant Contact Dermatitis (ICD) and Allergic Contact Dermatitis (ACD)

Irritant Contact Dermatitis (ICD)Allergic Contact Dermatitis (ACD)
Clinical Manifestation

  • Xerosis

  • Erythema

  • Pruritus

  • Burning

  • Fissuring

  • Scaling

  • Lichenification

  • Mostly limited to site of exposure (Figure 1)

  • Erythema

  • Pruritus

  • Edema

  • Induration

  • Vesicles, bullae, crusting

  • Fissuring

  • Lichenification

  • Spreading over site of exposure (Figure 2)

Pathophysiology

  • Non-immune response to repeated exposure to agents

  • Disrupted skin integrity

  • Loss of moisture and protective lipids

  • Immune-mediated response to allergens

  • Sensitization results in cell-mediated inflammatory cascade

Causative Agents

  • Detergents

  • Disinfectants

  • ABHRs

  • Water

  • Fragrances

  • Often related to atopic predisposition

  • PPE (eg, gloves)

  • Latex

  • Rubber compounds

  • ABHRs

  • Fragrances

  • Propylene glycol

  • Any possible contact allergen

Treatments

  • Avoidance of known irritants

  • Emollients

  • Keratolytics

  • Topical steroids

  • Avoidance of allergens

  • Emollients

  • Topical steroids

  • Modifications to occupation

Diagnostic

  • Patch tests to rule out ACD (diagnosis by exclusion) with decrescendo reactions in patch tests*

  • Fungal culture (exclude Tinea)

  • Biopsy if suspicion for Psoriasis

  • Evaluation of atopy (history, spec IgE, prick tests)

  • Patch tests to find causative agents and allow allergen avoidance with crescendo reactions in patch tests*

  • PPE, personal protective equipment; ABHR, alcohol-based hand rub.

  • ↵* Decrescendo reactions mean that after 2 days (removal of patch tests), there is a slight reaction that disappears the next 2 days. Crescendo reactions mean that there is no or slight reaction at day 2 (removal of patches) followed by an increased reaction the next 2 days. This difference is why we need 2 readings to distinguish irritants from allergic reactions, which is particularly important in atopic individuals with a high risk for irritant reactions. Most patients with irritant hand dermatitis have an atopic predisposition.