What is the difference between senile lentigines and melasma?

The main differences between senile lentigines and melasma are as follows: 1. **Etiology**: Senile lentigines are benign skin lesions associated with skin aging, genetic factors, sun exposure, and other factors. Melasma, on the other hand, is a pigmentation disorder related to genetic predisposition, ultraviolet radiation, hormonal changes, and other factors. 2. **Anatomical Distribution**: Senile lentigines can occur on any part of the body except oral mucosa, palms, and soles, and are most commonly found on the face, dorsa of hands, chest, and back. Melasma typically occurs on sun-exposed areas such as the cheeks, forehead, upper lip, nose, and jaw. 3. **Clinical Presentation**: Senile lentigines are usually brown to black macules, flat papules, or plaques, sometimes with a rough surface. Melasma presents as light yellowish-brown, dark brown, or deep coffee-colored macules of varying sizes with clear borders and symmetrical distribution. 4. **Treatment**: Senile lentigines are commonly treated with cryotherapy, laser therapy, surgery, or medication. Melasma is primarily managed with medication, while refractory cases may be treated with laser therapy or intense pulsed light therapy.