Spotting a new brownish mark on your forearm, shoulder, or face often sparks a quick question: Is this just a new summer freckle, an age spot, or a new mole that needs medical attention? As we age, our skin accumulates a variety of pigmented lesions. Distinguishing between freckles, lentigines, and true melanocytic nevi is an essential part of informed skin monitoring.

1. Freckles (Ephelides)

Freckles are small (1 to 2 mm), flat, light-brown spots that develop primarily on sun-exposed areas in genetically susceptible individuals (often with the MC1R gene variant). Key traits:

  • They do not involve an increased number of melanocyte cells; rather, existing cells overproduce melanin in response to UV stimulation.
  • Freckles characteristically darken during summer months and fade significantly during winter.
  • They are completely flat and never elevated above the skin plane.

2. Solar Lentigines (Sun Spots or "Age Spots")

Solar lentigines are larger (often 3 to 15 mm), flat, well-defined tan or brown patches caused by localized proliferation of melanocytes from cumulative lifetime UV exposure. Unlike freckles, solar lentigines do not fade in the winter and remain permanently visible on the hands, face, and shoulders.

3. Seborrheic Keratoses ("Barnacles of Aging")

Extremely common in adults over age 40, seborrheic keratoses are non-cancerous benign epidermal growths that often look "pasted on" the skin like candle wax or velvet. They can be light tan, dark brown, or black, and have a distinctly warty or crumbly texture.

4. Newly Acquired Melanocytic Nevi (Moles)

True moles involve nests of melanocyte cells growing in clusters. Most people develop their complement of moles between childhood and age 25. Developing numerous new moles after age 35 to 40 is less common and warrants closer photographic tracking, as newly acquired pigmented lesions in older adults have a statistically higher rate of being atypical or malignant.

Monitor Your Skin & Moles Confidently

Spot changes before they escalate. Capture clinical-grade photo timelines, map spots on an interactive 3D body map, and share structured reports with your dermatologist.

Download Mole Tracker Free on iOS

Frequently Asked Questions

How often should I check my skin for changing moles?
Dermatologists advise conducting a monthly photographic self-check to spot changes early, combined with an annual in-person clinical exam by a board-certified dermatologist.
Can smartphone apps diagnose skin cancer?
No smartphone app can replace a medical biopsy. Apps like Mole Tracker provide essential self-monitoring, visual timelines, and ABCDE triage to help you share organized reports with your doctor.
What is the best way to track moles over time?
Use a specialized tracking app with an interactive body map and side-by-side photographic comparison under consistent lighting to objectively identify changes in size, border, or color.
Anna Brown, MSc

Anna Brown, MSc

Lead Clinical Writer

Anna is a medical health writer specializing in cutaneous oncology, dermoscopy, and AI dermatology. Her guides are verified against WHO, AAD, and peer-reviewed clinical literature.

View All 21 Articles by Anna Brown →

Scientific References & Clinical Studies

  1. Differential Diagnosis of Pigmented Skin Lesions — American Family Physician Journal
  2. Seborrheic Keratosis and Solar Lentigo Clinical Profiles — Mayo Clinic Clinical Reference

Related Skin Health Guides

Is My Mole Normal? Complete Guide
Self-Check • 7 min
Can Normal Moles Turn Into Melanoma?
Clinical • 6 min