Citation: Elloudi S, Kamli N, Mernissi FZ. Localized psoriasis post hand burn. A total endoscopic approach. J Clin Images Med Case Rep. 2021; 2(2): 1053.

Clinical image description

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].

Figure 1: Clinical and dermoscopic appearance of the lesion of the back of the hand. A: Psoriasis lesions on the burn scar. B: Homogeneous vascularization with whitish scales.

The avoidance of trauma and friction is one of the hygienic measures to be adopted in a psoriatic patient

References

1. Ju-Hyun Jo, Ho-Sun Jang, Hyun-Chang Ko, Moon-Bum Kim, Chang-Keun Oh, et al. Pustular psoriasis and the Kobner phenomenon caused by allergic contact dermatitis from zinc pyrithione-containing shampoo Contact Dermatitis. 2005; 52: 142- 144.
2. Daniela P. Sanchez , Sidharth Sonthalia. Koebner Phenomenon 2020 Dec 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021. Stat Pearls. 2021.