Symmetic Drug Related Intertrigenous and Flexural Exanthema
Allergic Contact Dermatitis
Allergic contact dermatitis (ACD) secondary to topical medications is characterized by an eczematous eruption–which typically localized to sites of direct exposure. Depending on the severity and chronicity of ACD, eczematous eruptions can range from localized erythema and edema to vesicularization, crusting and weeping. However, ACD can become generalized to non-exposed sites, referred to as “autoeczematization” or “id reaction.”
The differential diagnosis for ACD also includes irritant contact dermatitis as well as other chronic eczematous dermatoses (e.g., atopic dermatitis, psoriasis).
The top 4 drug category causes of ACD are: antibiotics, local anesthetics, corticosteroids, and propylene glycol (techically an excipient).
Antibiotics (e.g., neomycin, bacitracin, polymyxin B) are the most common cause of ACD. Therefore, it is recommended to use petrolatum or other bland emolients for wound care because have equally low infection rate as bacitracin and other topical antibiotics without the risk of ACD.
Co-sensitization—when sensitized to ≥ 2 structurally distinct allergens—often occurs in patients who experience ACD. Therefore, when possible, it is important to test to individual components of a culprit topical drug.