Improvement of Pigmented Skin Lesions in Patients With Mastocytosis After Performing 2 Sessions of Pigment Laser
Improvement of Pigmented Skin Lesions in Patients With Mastocytosis After Performing 2 Sessions of Pigment Laser
Cutaneous mastocytosis can be isolated or associated with systemic involvement. Urticaria
 pigmentosa affects around 80 to 85% of adult patients with cutaneous mastocytosis. It is also
 frequently present in patients with mastocytosis associated with systemic involvement (80% of
 patients in our experience).

 This skin damage is one of the causes of deterioration in quality of life in patients with
 mastocytosis, through the loss of self-esteem, due to the appearance of lesions. However
 there are not treatment for urticaria pigmentosa.

 Skin involvement in mastocytosis is linked to the accumulation of abnormal mast cells in the
 dermis. However, the mast cells are not pigmented and the brown-brown color characteristic of
 Urticaria pigmentosa is explained by melanin pigmentation of the epidermal basal layer.
Cutaneous mastocytosis can be isolated or associated with systemic involvement. Urticaria
 pigmentosa affects around 80 to 85% of adult patients with cutaneous mastocytosis. It is also
 very frequently present in patients with mastocytosis associated with systemic involvement
 (80% of patients in our experience).

 This skin damage is one of the causes of deterioration in quality of life in patients with
 mastocytosis, through the loss of self-esteem, due to the appearance of lesions. However
 ,there is not a treatment for urticaria pigmentosa.

 Skin involvement in mastocytosis is linked to the accumulation of abnormal mast cells in the
 dermis. However, the mast cells are not pigmented and the brown-brown color characteristic of
 pigmentary urticaria is explained by melanin pigmentation of the epidermal basal layer. This
 characteristic is often described on skin biopsies of pigmentary urticaria analyzed in
 hematoxilin-eosin.

 The 532 nm Q-Switched laser is known to improve lesions characterized by the presence of
 melanin pigment in the basal layer of the epidermis, with very little risks. This later is
 explained by the reduced penetration of light at 532 nm into the skin and the emission time
 of the laser light which is very low (of the order of a few nanoseconds) for Q-Switched
 lasers. In the literature, 2 case reports report an efficiency of the laser at 532 nm in this
 indication in adults.

 The hypothesis of this study is that 2 sessions of Q-switched laser could improve the skin
 lesions of urticaria pigmentosa, leading to an improvement in self-esteem.
Inclusion Criteria:

 -  Patient with mastocytosis (diagnosis confirmed clinically according to international
 criteria)

 -  Patient with pigmented skin lesions, of moderate to very severe severity (by
 comparison with a 4-point photographic scale: light, moderate, severe and very severe)

 -  Major patient aged ≥ 18 years.

 -  Patient with social security coverage

 -  Patient having given written, free and informed consent to participate in the study

 Exclusion Criteria:

 -  Patients with mastocytosis, without skin lesions

 -  Patient with pigmented skin lesions, only of mild severity (by comparison with a
 4-point photographic scale: mild, moderate, severe and very severe)

 -  Patient with another cutaneous mastocytosis phenotype

 -  Patient treated by a treatment known as a cytoreductive for mastocytosis: alpha
 interferon, cladribine, imatinib, midostaurin or any cytoreductive treatment being
 evaluated by clinical trial in mastocytosis

 -  Patient under guardianship, or under curatorship, or not fluent in the French language
 or unable to understand and complete the study questionnaires

 -  pregnant or breastfeeding women

 -  Patients with tanned skin following photoexposure within 3 weeks of starting the study