Localized psoriasis post hand burn

The Koebner Phenomenon (KP) is the appearance of new skin lesions on previously unaffected skin secondary to trauma. This phenomenon is given the fact that the new lesions that appear are clinically and histologically identical to the patient's underlying cutaneous disease [1]. Psoriasis is a chronic inflammatory disease characterized by this phenomenon. A patient with psoriasis will develop new psoriasiform lesions at any anatomical site on the body, including friction areas or areas exposed to trauma such as the hands. We report here the case of a 37-year-old patient, followed in our training for plaque psoriasis for 5 years, who was put on topical corticosteroids and phototherapy with improvement. The patient suffered a superficial 2nd degree thermal burn to the back of her left hand. During the epidermis phase of her burn, the patient showed small erythematosquamous papules within the burnt area, dermoscopic examination of which revealed a homogeneous vascularization with whitish scales in favor of psoriasis lesions in drops (Figure 1). A class strong topical corticosteroid is initiated with good improvement. Potential mechanisms include alteration of polymorphonuclear leucocyte chemotaxis, diminished or enhanced synthesis of arachidonic acid metabolites, changes in the cyclic nucleotide system and modified lymphokine production [2]. The avoidance of trauma and friction is one of the hygienic measures to be adopted in a psoriatic patient