Allergy Patch Test showing allergic reaction to Balsam of Peru The diagnosis of<unk>  is from taking history and inspection of the rash. It is important to distinguish it from allergic contact dermatitis and perioral dermatitis which are characterized by papules in the perioral area and sparing of the vermillion border, and worsened by topical steroids. Allergic contact dermatitis can be differentiated from irritant contact dermatitis by the presence of antigen specific T cells since allergic contact dermatitis is a response of delayed type IV hypersensitivity mediated by T cells. Additionally, people with irritant contact dermatitis will present with a burning sensation rather than an itching sensation, which is different from allergic contact dermatitis. Allergy patch skin tests can be used to differentiate allergic contact dermatitis from irritant contact dermatitis and to identify causative allergens if dermatitis has allergic nature. This is done by inducing a small eczematous reaction by administering allergens under occlusions on intact skin. The T.R.U.E (Thin-layer Rapid-Use Epicutaneous) Test is an easy to use and convenient product available with 35 allergens suspended in gels and is commonly used by dermatologists and allergists. Differentiating between acute or chronic irritant dermatitis can also help in diagnosis and treatment. Chronic dermatitis is the more common form usually defined as more than 6 weeks of skin irritation. This is usually caused by regardless of moisturizer effectiveness, there is still frequent and repetitive exposure of irritant can exceed skin recovery time.<unk>  can also be confused with Angular cheilitis which can present as similar symptoms around the mouth as erythema or ulcerations. The difference is,<unk>  often spares the corner of the mouth while Angular cheilitis results in crusting at the corners of the mouth caused by irritant or allergy.
Lip licker's dermatitis
African blackwood dermatitis
Lacquer dermatitis
Diabetic dermadrome
Phototoxic tar dermatitis
Abietic acid dermatitis
Cat-scratch disease
Blister beetle dermatitis