Skin Lesions · What Are They, Types, Causes, Diagnosis, Treatment, and More

Skin lesions can present in a variety of different sizes, shapes, and forms. Moreover, skin lesions can appear isolated or in groups, and either localized in a single area or widespread throughout the body. 

Keratinocyte carcinoma arises from skin cells called keratinocytes, and includes basal cell carcinoma and squamous cell carcinoma. Basal cell carcinoma can appear as a pearly, flesh-colored skin lesion, with superficial blood vessels called telangiectasias on top. Basal cell carcinoma may present as a superficial scaling plaque, or a non-healing sore, which may bleed or form a crust. Conversely, squamous cell carcinoma commonly appears as a thick, crusty sore, with a reddish, inflamed base that can ulcer (appear as an open sore) and bleed. 

Melanoma arises from skin cells called melanocytes. Melanoma typically looks like an abnormal or irregular mole. The main warning signs of melanoma can be assessed using the ABCDE rule. ABCDE stands for Asymmetry, Border irregularities, Color heterogeneity, Diameter over 6 mm, and Evolution, which refers to changes in size, color, or shape over time. The presence of one or more of these features indicates a higher chance of malignancy.

Unlike malignant lesions, benign skin lesions are generally symmetrical, well-circumscribed, have a uniform appearance, and are stable or grow slowly over time. However, in certain cases, it can be difficult to distinguish between benign and malignant lesions; in those cases, a biopsy or surgical removal of the affected area can be performed to rule out malignancy.

Individuals with AIDS can develop skin lesions as a result of the progressive immunosuppression caused by HIV infection. AIDS is associated with Kaposi sarcoma, an aggressive type of cancer that presents as red or purplish nodules and plaques on the skin and mucous membranes, such as the gums. Besides Kaposi sarcoma, individuals with HIV infection can develop severe opportunistic skin infections, as well as skin rashes (such as Stevens–Johnson syndrome) as a side effect of antiretroviral treatment. 

Diagnosis of skin lesions begins with careful physical examination and medical history. Physical examination involves assessing the color, size, shape, depth, location, and comparison with other lesions. Dermoscopy can be performed to examine skin lesions under a magnifying glass. A Wood’s lamp examination can also be used to evaluate certain skin conditions under a black light. Additionally, certain aspects of the medical history can offer valuable information to guide the diagnosis, including sun exposure, allergies, current medications, contact with irritants, previous malignancy, and family history.

Some skin lesions may require further diagnostic tests. These can include blood tests, allergy tests, skin or wound swabs for microbiological investigations, and imaging techniques, such as an X-ray or CT scan. Finally, if the diagnosis is still uncertain or malignancy is suspected, a biopsy can be performed.

Treatment of skin lesions can vary depending on the type of lesion and if malignancy is present. Some benign lesions may not need to be treated at all, and can be managed via regular check-ups with a dermatologist or general physician. 

If needed, benign skin lesions can get local treatment with topical medications, such as retinoids, corticosteroids, or antimicrobial agents, as well as laser therapy, cryotherapy, phototherapy, or surgical removal. If the skin lesion is caused by a systemic disease, treatment may also address the underlying cause. 

Malignant skin lesions are generally treated with surgical removal, which can be followed by radiation therapy, chemotherapy, or biological treatments like immunotherapy.