Background: Allergic scalp contact dermatitis (ASCD) is a delayed type of hypersensitivity from contact with a specific allergen to which the patients has developed a specific sensitivity. The aim of the study was to evaluate the results of patch testing with standard series of contact allergen in patients suspected to have ASCD. Methods: 112 cases of scalp contact dermatitis were included in the study. Test substances were applied on the upper part of the patient's back, on clinically uninvolved and untreated skin. The patch test was removed and reaction were evaluated after 48 h and 72 h. The grading of negative (-) to positive (+ to ++++) patch test was done in accordance with the International Contact Dermatitis Research Group. Results: Among the 112 cases, 83 patients were female (74.1 %) and 29 were male (25.9 %). The age of participants spanned 17 to 72 years. The commonest age group affected was 41-50 years. The most common positive reactions were recorded to nickel sulphate 22 (26.2%), cobalt chloride 18 (21.4%), fragrance mix 16 (19%), balsam of Peru 14 (16.7%), carba mix 8 (9.5%) and paraphenylenediamine 5 (5.9%).  Females were more likely to show a positive response to two or more allergens. Scalp itching or burning were reported as the most common symptom. Conclusions: Scalp ACD predominantly affects middle-aged women. Our results suggest that nickel sulphate and cobalt are the predominant allergens responsible for the induction of ASCD. These findings are crucial in the treatment, long term management, and education of patients with ASCD.

Background: Allergic contact dermatitis (ACD) is a delayed type of hypersensitivity from contact with a specific allergen to which the patients has developed a specific sensitivity. The aim of the study was to evaluate the results of epicutaneous patch testing with standard series of contact allergen in patients suspected to have ACD. Methods: 355 cases of ACD were included in the study. Test substances were applied on the upper part of the patient’s back, on clinically uninvolved and untreated skin. All patients were free from therapy with oral antihistamines, steroids and immunosuppressants. The patch test was removed and reaction were evaluated after 48 h and 72 h. Grading of negative (-) to positive (+ to ++++) patch test was done according to the International Contact Dermatitis Research Group. Statistical data analysis was performed by using χ2–test. Results: Of the 355 cases, 146 patients were male (41.1%) and 209 were female (58.9%). The youngest patients in the study was 16 years of age and the oldest was 67 years of age. The commonest age group affected was 41-50 years. Hands were the most common site of involvement. The occupational character of skin lesions was find in 75 (21.1%). The most common positive reactions were recorded to nickel sulphate 99 (27.8%), cobalt chloride 46 (12.9%), thimerosal 31 (8.7%), colophony 23 (6.5%), carba mix 21 (5.9%), potassium dichromate 20 (5.6%), acid chromici 19 (5.3%), fragrance mix 18 (5%), balsam of Peru 13 (3.7%), formaldehyde 9 (2.5%), and other allergens 26 (7.3%). Females were significantly more likely to show a positive response to two or more allergens (p<0.05). There was no statistically significant impact of age, occupation and duration of disease on results of patch testing (p>0.05). Conclusions: Our results indicate that nickel sulphate, cobalt chloride and thimerosal are the most common allergens responsible for induction of ACD. These findings are crucial in the treatment, long term management, an education of patients with ACD.