What is Lentigo?
Lentigo is a small, sharply circumscribed, pigmented macule surrounded by normal skin. A lentigo is a small pigmented spot due to increased melanocytes in the epidermis, just above the basement layer; in contrast to moles that have a nest of melanocytes. Pigmentation may be homogeneous or variegated and can vary from brown to black in color. Lentigines usually are formed slowly over years, sometimes may suddenly erupt.
What are the causes?
Triggering factors that contribute depends upon the type of lentigo, usually, the following reasons are considered:
Prolonged or overexposure to sunlight or ultraviolet rays
Phototherapy or radiation therapy
Sunburns form early childhood
Fair skin, blond and red hair or light-colored eyes
Genetic and inherited disorders
Immunosuppression such as AIDS and Organ transplant patients
Hormonal changes during puberty, pregnancy and taking contraceptive pills
People of all ages and both genders can get lentigines.
Different Types of Lentigines:
Lentigines can grow to appear as single or in groups. Most lentigines are smaller than 5 mm in diameter.
1. Lentigo simplex is the most common type this often starts in early childhood or adult life and is the precursors of junctional nevi. They are present on your trunk, arms, and legs. These spots disappear over a time period in most cases. They are characterized by smooth or jagged edges and have a dry skin surface.
2. Solar lentigo is caused by exposure to ultraviolet radiation from the sun causing melanocytes in the skin to multiply. These are more common in people above 40 and are considered to be a precursor of seborrhoeic keratosis. Solar lentigines are called as liver spots or age spots. Solar lentigo appears on sun-exposed areas of the body, like the face, hands, shoulders, and arms. The spots may grow over time. They are very dry to touch with a faded outline and are yellow, light or dark brown in color and can be both, regular or irregular in shape.
3. Ink spot lentigo appears after sunburn in people who have lighter-pigmented skin. They are dark brown or black in color with irregular margins
4. PUVA lentigines: They are similar to ink spot lentigines and develop on areas exposed to PUVA therapy, which is used to treat chronic skin diseases such as psoriasis and eczema.
5. Radiation lentigines: These are more commonly seen in cancer patients and lentigines appear in areas exposed to radiation.
6. Tanning bed lentigines: features are similar to ink spot lentigines and appear on parts of body exposure to the indoor tanning bed.
7. Generalized lentigines: These tend to begin with small macules that later merge to form larger patches; noticed in children.
8. Agminated lentigines: These are a naevoid eruption of lentigines confined to a single segmental area.
9. Patterned lentigines: These patterned lentigines inherently develop on face, lips, buttocks, palms, and soles.
10. Melanotic macule: These are also called mucosal lentigines, as they develop over mucosal surfaces or to the adjacent glabrous skin like lip, vulva, penis, and anus. They are light to dark brown in color.
11. Centrofacial neural dysgraphic lentiginosis: These are associated with mental retardation.
12. Lentiginosis syndromes: The inheritance is autosomal dominant and sporadic cases are common. Widespread lentigines are present at birth or arise in early childhood. This syndrome is associated with neural, endocrine, and mesenchymal tumors. Following inherited syndromes can also be associated with lentigo are:
a. Peutz-Jeghers syndrome: This condition causes noncancerous growths to form in the stomach and intestines. Children with Peutz-Jeghers often involves their faces with multiple small brown to black lesions.
b. Cowden syndrome: This disorder causes many noncancerous growths called hamartomas on the body.
c. Noonan syndrome: This condition causes multiple lentigines to involve different parts of the body.
d. Bannayan-Riley-Ruvalcaba syndrome: This condition causes a larger-than-normal head, noncancerous tumors, and plenty of lentigenes on the body.
e. Xeroderma pigmentosum: This syndrome makes our skin extra sensitive to UV rays from sunlight.
Lentigo to be differentiated with the following conditions:
Even though lentigenes are sharply circumscribed, small pigmented macule surrounded by normal skin, you need to should differentiate in its early stage with other skin conditions mentioned below:
Freckles: They are tiny, flat, brownish-colored spots (3 mm) that typically appear on the face, shoulders, and neck.
Moles: Discrete Dark pigmented spots that do not increase in size and are benign in nature called moles.
Chloasma: In very early stages it has to be differentiated with lentigenes, the hyperpigmentation is due to an increase in pigment due to melanocyte normally during pregnancy is called Chloasma.
Birthmark: These skin marks appear at birth or just after birth, which is usually darker than the rest of the skin. The colors vary from pigmented to port-wine stain.
Lentigines are harmless; Different types of lentigines appear on different parts of the body. They do not itch nor cause pain and might vary in color from light brown to black. Normally they are flat and have even or uneven edges with associated problems.
Prevention of Lentigines
The following methods should be adopted to prevent the formation of lentigines:
Avoid prolonged exposure to the sunlight
Use sunscreen SPF >50
Reduction in the number of indoor tanning sessions
Take good nutritious diet and have a healthy lifestyle
Treatment of Lentigo
Treatments to lighten or remove lentigines are almost similar to freckles; lentigenes respond slowly to treatment.
Sun protection and regular use of sunscreen is the best way to prevent from occurring freckles.
Bleaching creams, containing hydroquinone and kojic acid, works better in combination with sun protection. Retinoids may be used in conjunction with other bleaching creams to enhance the lightening effect.
Chemical peels to lighten lentigenes.
Cryosurgery and Electrosurgery can destroy melanocytes.
Lasers & Light Therapy:
Several types of lasers and light are quite safe, with a high success rate with extremely low risk in treating freckles effectively. Among lasers, Q-switched lasers are the gold standard, with the highest success rate in treating freckles. Intense Pulse Light (IPL) treatments are quite effective another laser-based technique, to tackle freckles. In a few resistant cases, you may require a CO2 laser to eliminate.
Few are the other following treatments to be carried out if the above-mentioned treatment fails and for the associated disorders.
Surgery: The surgical removal of the tissue is slightly larger than the existing lentigo, to provide a safety zone. Prophylactic removal is performed; in the case of metastases, regional lymph nodes are removed through radical resection.
Radiation therapy: After surgical treatment, radiation therapy in large doses to be given in case of inoperable tumors.
Perfusion therapy: With cytotoxic agents to inhibit tumor growth in un-operated cases which include multiple recurrences or metastases.
Chemotherapy: Drugs such as bleomycin, vincristine, and lomustine are administered to the patient to suppress the development of cancer cells in the lentigines.
Glycosylated INF: This treatment deals with human interferons used in combination with other drugs to treat metastatic disease.
Gene therapy: This vaccinates and immunizes individuals against the tumor.