Contact dermatitis caused by ballpoint pen ink: A problem for a schoolchild

Abstract

A 14-year-old boy was referred because of the presence of itchy multiple tiny blisters over the forearm for 3 days, appearing after drug sensitivity testing for penicillin on the volar aspect of the forearm 4 days earlier. During this procedure, the site of injection was encircled with a blue ballpoint pen by the attending nurse. Moreover, the date and time of injection had been written just above the circled area. The ink on these latter sites later accidentally contaminated the anterior aspect of the arm after flexing of the elbow. On clinical examination, multiple pinhead-sized vesicles arranged in a circular pattern over an erythematous base around the site of test injection were seen. Similar lesions were present in a horizontal line just above this, exactly where the date and time were written, and also over the lower aspect of the arm opposing this line ( Figure 1).On the basis of this clinical picture, an allergic reaction to either the ink or the metallic tip of the pen was suspected. We retrieved the pen from the nurse who had performed the test. Patch testing with the Indian baseline series, cosmetic series and footwear series was performed (Systopic Pharmaceuticals, New Delhi, India) with aluminium Finn Chambers, and the results were interpreted according to ICDRG recommendation. In addition, the patient was tested with the ink of the obtained pen "as is." To this end, the pen was cut in half, and the ink was squeezed out and placed in one of the chambers, thereby avoiding skin contact with the metallic tip of the pen. The results were read on day (D) 3, and showed a positive reaction to ink (+) and negative results for all other allergens (Supporting Information Figure S1a-c). This confirmed the diagnosis of allergic contact dermatitis caused by ballpoint pen ink. To more precisely identify the allergen (colouring agent or solvent), we obtained the same pen with all the colours that were available on the market, that is, black, blue, red, green, and blue. This time, the patient was subjected to patch tests with inks of the obtained pens, with the same procedure as used in the previous test. To our surprise, besides blue ink, the patient showed a positive reaction to red ink (Supporting Information Figure S2a,b). The responses to other colours (black and green) were negative, which ruled out the possibility of contact allergy to a solvent common to pens of all colours. DISCUSSIONContact dermatitis caused by colouring agents and ink used in tattoos, hair dyes and henna is well known, with allergens such as mercury salt (red), dichromate (green), cobalt (blue), cadmium (yellow) pigments and FIGURE 1 Clinical picture showing multiple tiny vesicles over the volar aspect of the left forearm and lower aspect of the arm. The lesions where the site of injection was encircled are present in a circumferential pattern (red arrow). The yellow arrow points to the lesion where the date and time were written horizontally, and the green arrow points to the lesions where the ink became smudged on flexing of the elbow ...