We report a case of a 73 year old man presenting with a non healing wound on his right forearm for 4 weeks. The wound started from an insect bite and progressively enlarged with increasing pruritus and burning sensation. Clinically an ill-defined ulcer was seen on his right forearm with surrounding erythema and erosion. There was a yellow crust overlying the center of the ulcer and the periphery was scaly (Figure 1). Further inquiry revealed history of self treatment with a yellow solution to clean his wound for 3 weeks. He could not recall using the solution in the past and did not seek any medical advice prior to the current visit. Patient was provisionally diagnosed to have allergic contact dermatitis secondary to acriflavine. Acriflavine usage was stopped and the ulcer was treated with daily non-occlusive saline dressing. The lesion improved a week later looking noticeably dry, less inflamed and smaller in diameter (Figure 2). At the end of two weeks, there was complete resolution of the ulcer, leaving a residual post-inflammatory hyperpigmentation. A patch test using Standard European series (Chemotechnique) containing 28 different allergens and acriflavine was done seven months later. The result showed a positive reaction (2+) to acriflavine while the rest were negative.
Acriflavine or commonly known as Flavin, is an acridine derivative of proflavin used as a topical antiseptic agent. It is a yellow or orange colour solution which stains the skin and may cause irritation, inflammation or blister upon contact [1]. It is commonly used as skin disinfectant for minor wounds, burns, infected skin and is effective against both gram positive and negative bacteria [1]. Acriflavine was initially used during the First World War as a treatment for African trypanosomiasis (sleeping sickness). In addition to its disinfecting property, it has also been shown to inhibit cancer progression in animals [2]. Although used in dilution (0.1%), it has been documented to produce potential skin irritation and is still widely used for wound dressing in both hospitals and outpatient clinics.
Contact dermatitis is an eczematous symptom occurring as a result of skin exposure to an irritant or sensitizing agent. It is generally categorized as allergic contact dermatitis and irritant contact dermatitis. Allergic contact dermatitis is an immune mediated inflammatory reaction while irritant contact dermatitis is a non-allergic inflammatory reaction causing direct cell damage resulting in skin dryness, redness or even burns [3]. Common antibacterials and antiseptics that cause an allergic reaction are Neomycin (40.6%), Soframycin (15.1%), Dettol (10.9%), Savlon (8.3%) and Acriflavine (5.2%) [4, 5]. Besides contact dermatitis, acriflavine has also been shown to cause perioral and mucosal odema [6].
Individuals of all age groups and ethnicity have potential risk for developing contact dermatitis ranging from diaper dermatitis in infants to hair dye and fragrance dermatitis in the elderly [1]. Various studies have shown increasing prevalence of contact dermatitis to topical medicaments with advancing age [7, 8]. This is probably due to the fact the elderly have been exposed to multiple allergens during their life time compared to younger individuals. Atopic individuals were previously thought to be more susceptible to contact dermatitis. However, a definite relationship between atopic dermatitis and contact dermatitis is yet to be established as current evidence show controversial results [1].
Typical features of dermatitits medicamentosa are non healing wound, worsening or enlarging wound with presence of surrounding dermatitis. Staining of the wound provides a clue to identify the irritant; yellow (acriflavine) or dark brown (potassium permanganate). The reaction is usually gradual and not an acute event. Hence patients are usually unaware of the underlying cause for the reaction which further delays wound healing. Withholding the irritant and appropriate topical management speeds up recovery.
Patch test is the gold standard for detection and confirmation of contact dermatitis. This is a simple yet cost effective test that facilitates early and accurate detection of underlying cause for suspected contact dermatitis [9]. It also serves as an important tool in patient education to avoid further exposure to the known allergens. Although the test is simple to perform, adequate experience and training is required for accurate interpretation of the results. Patch test is best avoided during an acute reaction and performed about six months after an initial contact to prevent further aggravation of the existing dermatitis [1].
