Common causes of back blackness like dirt include melanosis, post-inflammatory hyperpigmentation, chronic eczema, and skin amyloidosis.
1. Melanosis: Melanosis, also known as melanosis, is of unknown etiology and pathogenesis, and may be caused by long-term use of contact photosensitive substances, such as tar, asphalt, etc., or long-term use of certain medications, such as antimalarials, chemotherapeutic drugs and other factors. It manifests as symptoms such as darkened, brown, blue-gray skin with small pigmented spots around the edges of hair follicles. It can be relieved after treatment.
2. Post-inflammatory hyperpigmentation: this disease is mainly caused by inflammatory skin diseases, such as lichen planus, lupus erythematosus, pityriasis rosea, insect bite dermatitis. It is manifested in the skin as light brown, purple-brown to dark black pigmented spots, and the color will be aggravated after sun exposure or re-inflammation. After standardized treatment, the symptoms can be relieved.
3. Chronic eczema: the cause of this disease is unknown, may be in a hot and humid or dry environment for a long time, long-term contact with irritating substances, such as chemical fibers, soaps, etc., or caused by scratching for a long time. Manifestation of skin erythema, papules, papules, itching, hyperpigmentation spots and other symptoms.
4. Skin amyloidosis: the etiology is not clear, mostly related to genetic and metabolic disorders. It is characterized by black hyperpigmented papules, hyperkeratosis of the tip, roughness and itching. It is not curable at present, but the symptoms can be relieved by regular treatment.
It is recommended that patients go to the dermatology department of regular hospitals in a timely manner to get a clear diagnosis and follow the doctor’s instructions for reasonable treatment, so as to avoid delaying the condition.