In the dermatological vocabulary, the term spot is defined as a skin rash that meets several conditions at the same time. The spot on the skin should:
- be clearly defined from the surrounding normal skin,
- not be palpable to the touch,
- be on the same level as the surrounding skin (that is, on the same plane),
- differ from the surrounding skin only by color.
The success or failure of a depigmenting treatment lies in a good identification of the spot to be treated, and therefore, it is important to specify in which histological level the melanin pigment is located.
In the efficacy studies, we first relied on the dermatological diagnosis using Wood’s lamp, called the black light test or the ultraviolet light test.
This lamp is used to determine the depth of the spot, which is essential when choosing the spot, we are going to study.
The depigmentation treatment is different depending on the type of spot, its depth and the type of skin of the subject, since it will vary according to whether the spots are superficial or deep. For the effectiveness studies of a depigmenting product we will choose superficial hyperpigmentation, which respond very well to cosmetic treatments.
For the evaluation of the effectiveness of a depigmenting product we will measure the melanin content of the skin with the Mexameter® MX 18 (Courage + Khazaka electronic GmbH).
Throughout the study, we will quantify the melanin content inside the spot and also in an adjacent area of normal coloration. In this way we can evaluate the depigmenting efficacy from two points of view, verifying the decrease in the melanin content of the spot and also the unification of the tone between the spot and the adjacent area.
For a correct execution of the experimental phase, it is essential to always use sun protection.