Naevi

Naevi, the medical term for moles, are commonly raised or flat spots that occur on the skin genetically or as a result of sun exposure. These common skin lesions are formed when melanocyte cells (the cells that give pigment to our skin) grow in a group rather than individually. Most moles are benign, but it is possible that they develop into skin cancer.

Harmless moles usually:

have neat edges
are smooth or dome-shaped
are around ¼ inch (6 mm) in diameter
preserve the same shape, size or color over time.

On the other hand, cancerous moles have a few common warning signs you should watch out for :

A change in size (getting larger)
A change in shape (especially with irregular edges)
A change in color (especially getting darker or exhibiting multiple shades)
A loss of symmetry (common moles will be perfectly round or oval and are usually symmetrical)
Itchiness, pain or bleeding (maybe even forming a scab)
Crustiness
Inflammation
Exhibiting three different shades of brown or black
A change in elevation (thickening or raising of a flat mole)

Common skin lesions

Acne

Acne is a widely common skin condition that ranges from mild to severe. The condition usually appears as skin bumps that often become red or swollen. Acne can also take the form of whiteheads, blackheads, papules, pustules, cysts or nodules. Severe acne can leave scars if not treated in time. Many acne treatments are available, ranging from topical products to prescription medication. A dermatologist should prescribe the appropriate treatment.

Hives

Hives are a rash of red bumps that occur suddenly on the skin usually as a result of an allergen. These common skin lesions typically last from a few hours to a few days before subsiding. Hives are widespread and can show up anywhere on the body; they can even move around, disappear, and reappear over a matter of hours. Treatments are directed at the symptoms until the hives disappear on their own. Usually, antihistamines are recommended.

Eczema

Eczema, also known as atopic dermatitis, is a skin condition that causes red, itchy, and dry skin as a result of inflammation. Sometimes, white patches or spots can form within a red rash. This condition is typically found in children but can also appear in adulthood. Eczema symptoms include dry, scaly, thickened skin that is almost always itchy. Especially among dark-skinned people, eczema can cause skin discoloration, making the affected area lighter or darker than the surrounding skin.

The cause of eczema is unknown but it is thought to be linked to allergies and asthma and is suspected to be an overactive immune response to an irritant. While there is no cure for the condition, symptoms can be managed. For many people, eczema will even go away over time. Doctors can prescribe topical corticosteroid creams and ointments, oral medications and light therapy to help ease symptoms.

Rosacea

Rosacea is a chronic skin condition that appears in the form of tiny red pimples and redness. This skin condition occurs mostly on the face and causes small blood vessels to appear on the surface of the skin. Rosacea often starts as a tendency to blush or flush easily. The condition can also make skin thick and cause acne-like breakouts. It is usually treated with topical ointments, antibiotics, and lasers.

Seborrheic dermatitis

Seborrheic dermatitis is a skin condition where a red, itchy, and scaly rash develops, typically on the scalp, but also in other areas of the body. It often looks similar to psoriasis, eczema or a rash from an allergic reaction. The rash isn’t contagious and can often remain on the skin for an extended period. Symptoms can include dandruff, greasy, and scaly skin, red skin or crusting, and sometimes itching or stinging. Although its exact cause is unknown, seborrheic dermatitis can be treated with creams, shampoos, ointments, and antifungal or other medications that affect the immune system.

Psoriasis

Psoriasis is a chronic skin disease that causes red, scaly, and itchy plaques to form on the skin. It is caused by skin cells multiplying faster than normal. Psoriasis can also take the form of small red spots, pus-filled bumps, red patches that feel sore or skin that becomes bright red and appears burnt. It often occurs on the knees, elbows, and scalp, and, although it is incurable, it usually responds well to treatment. Treatments include topical creams, medicines, and ultraviolet light treatments.

Vitiligo

Vitiligo is a disease in which the skin forms white patches. It occurs when melanocyte cells stop producing melanin, either because they die or because they stop functioning. Causes of vitiligo are unclear, but this skin condition is thought to be an autoimmune disease. It can appear at any age and on any part of the body. Sometimes, the white patches will spread throughout the body, while other times they will remain the same size. Vitiligo often appears initially as a small, pale spot on the skin that, over time, will develop into a larger patch.

Vitiligo is generally harmless and not contagious, but its aesthetic appearance can cause emotional and psychological distress in people who suffer from it. Several treatments can help reduce the appearance of vitiligo, including corticosteroid creams, depigmentation treatments, and UVA and UVB phototherapy. Some of these treatments come with side effects, so it is recommended to discuss options with a doctor.

Impetigo

Impetigo is a contagious bacterial infection of the skin. This type of common skin lesions is mostly found in children rather than in adults and is caused by the Staphylococcus (staph) and Streptococcus bacteria. Impetigo appears as small red spots that morph to blisters that eventually break open and ooze fluid. Sores may also be crusty and can range in size from the size of a freckle to larger than a coin. Impetigo is usually treated with antibiotics, in the form of pills or an ointment.

Warts

Warts are small benign tumors caused by one of over 100 types of human papillomaviruses (HPV). Warts are often contagious and can be spread through physical contact. Many different types of warts can occur on the body. Common warts usually grow on fingers, nails and the back of hands. They typically appear as domed, rough bumps. Contact a doctor to identify which type of wart you have and to follow the right course of treatment. Warts can often disappear on their own, but a dermatologist can also treat them. The most common treatment is cryotherapy. Excision, electrosurgery, and curettage are other standard treatment options.

Skin cancer

There are many different kinds of skin cancer, separated into non-melanoma and melanoma skin cancers. Basal cell carcinoma is the most common form of skin cancer and the least dangerous, usually appearing as a small lump that gets bigger over time. Squamous cell carcinoma is less common and spreads faster. It often appears as rough, scaly plaques that can bleed easily. Melanoma is the most dangerous form of skin cancer, typically developing from a new mole on the body. Skin cancer treatments range widely based on the type, severity, and health of the patient. Any suspicious marks should be checked out by a doctor as soon as possible. Learn more about skin cancer symptoms.