Hypopigmentation is a heterogeneous group of dermatological conditions in which there is a decrease in the melanin content in the skin due to a disturbance in its synthesis, transport, or a decrease in the number of functionally active melanocytes. Despite the similarity in clinical presentation, these conditions have different origins, ranging from genetically determined syndromes to acquired inflammatory and post-traumatic changes. This significantly complicates differential diagnosis and requires a systemic, pathogenetically oriented approach. The review summarizes data from Russian and foreign publications for 2014—2024 and proposes a classification of hypopigmentations based on the mechanisms of damage to the melanocytic apparatus. Within this model, post-traumatic hypopigmentation is divided into 3 types: epidermal, follicular, and dermal cicatricial. This division reflects the depth of damage to the melanocytic niche and the degree of preservation of melanocytic stem cells, which is directly related to the likelihood of spontaneous repigmentation and the choice of treatment tactics. For each variant, characteristic clinical and dermatoscopic signs are described, as well as therapeutic algorithms — from observation and topical stimulation of melanogenesis to the use of phototherapy and surgical methods of pigment reconstruction. Key links of pathogenesis, including oxidative stress, dysregulation of the Wnt/β-catenin and SCF/c-kit signaling pathways, as well as the contribution of immune inflammation to maintaining melanocyte damage, are considered. The role of non-invasive diagnosis in assessing the integrity of the follicular reserve and predicting the outcome is emphasized. The proposed systematization allows for structured clinical thinking, improved treatment selection accuracy, and minimization of psychosocial consequences for patients.
Petunina et al. (Fri,) studied this question.