Psoriasis is a chronic autoimmune skin condition characterized by the rapid turnover of skin cells, leading to the formation of red, scaly patches on the skin. It primarily affects the scalp, elbows, knees, and lower back but can appear anywhere on the body. The condition is not contagious and is often triggered by factors such as stress, infections, or skin injuries.
Psoriasis is a chronic autoimmune condition characterized by rapid turnover of epidermal keratinocytes. The pathogenesis involves:
Psoriasis is marked by well-demarcated erythematous plaques with silvery scales, commonly found on the scalp, elbows, knees, and lower back.
Type of Psoriasis | Description |
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Plaque Psoriasis | Thick, red plaques covered with silvery-white scales. |
Guttate Psoriasis | Small, drop-like lesions, often triggered by streptococcal infections. |
Inverse Psoriasis | Occurs in skin folds, with smooth, red patches. |
Pustular Psoriasis | Characterized by white pustules surrounded by red skin. |
Erythrodermic Psoriasis | A severe, potentially life-threatening form that involves widespread redness and scaling. |
Diagnosis is clinical, based on the characteristic appearance of plaques. A biopsy may be performed to rule out other conditions in atypical cases. Key histological features include acanthosis (epidermal hyperplasia), parakeratosis(retention of nuclei in the stratum corneum), and Munro microabscesses (collections of neutrophils in the epidermis).
Psoriasis treatment is based on the severity of the disease:
Psoriasis is associated with several comorbidities, including psoriatic arthritis, cardiovascular disease, and metabolic syndrome. Psoriatic arthritis affects up to 30% of psoriasis patients and can lead to joint destruction if untreated.
Basal cell carcinoma (BCC) is a common skin cancer originating from the basal cells in the epidermis. It typically manifests as a pearly bump or a flat lesion in sun-exposed areas, such as the face and neck. BCC grows slowly and is unlikely to metastasize, making early detection and treatment important.
OBRAZEK
Basal cell carcinoma is the most common type of skin cancer, arising from the basal cells in the epidermis. It is caused by DNA mutations, primarily due to UV radiation exposure, leading to uncontrolled cell growth. BCC is a locally invasive malignancy that rarely metastasizes.
A clinical diagnosis is typically followed by biopsy to confirm the histopathology. BCC shows basaloid cells in the epidermis, with palisading nuclei and clefts between tumor cells and stroma.
BCC has an excellent prognosis with appropriate treatment, but recurrence is possible, especially in high-risk or poorly treated cases.
Squamous cell carcinoma (SCC) is a type of skin cancer that originates in the squamous cells of the epidermis. It commonly appears as a firm, red nodule, a flat sore, or a scaly patch, often on sun-exposed areas such as the face, ears, and hands. SCC can grow more aggressively than basal cell carcinoma and has a higher risk of metastasis if not treated promptly.
OBRAZEK
Squamous cell carcinoma arises from keratinocytes in the epidermis and can develop from actinic keratoses, which are premalignant lesions caused by chronic UV exposure. Other risk factors include immunosuppression, HPV infection, and chronic wounds.
SCC typically appears as a firm, red nodule or a scaly, crusted lesion. It may ulcerate or bleed, particularly in sun-exposed areas such as the face, neck, arms, and hands. High-risk SCCs include lesions on the ears, lips, and genitalia, as well as those that are large, deep, or rapidly growing.
Diagnosis is confirmed by biopsy, revealing atypical keratinocytes extending beyond the epidermis into the dermis. Keratin pearls (whorls of keratinization) are often seen histologically.
SCC has a good prognosis when treated early, but advanced or high-risk cases can metastasize to regional lymph nodes or distant organs.
Melanoma is a type of skin cancer that develops in melanocytes, the cells responsible for producing melanin, the pigment that gives skin its color. While it primarily occurs in the skin, it can also manifest in other parts of the body, such as the eyes, mucous membranes, and rarely in internal organs.
OBRAZEK
Melanoma has seen a steady increase in incidence over the past few decades, especially in regions with high sun exposure. Risk factors include:
A dermatologist typically performs a thorough skin examination to evaluate moles for suspicious characteristics. Two widely used systems aid in evaluating suspicious skin lesions: the ABCDE criteria and the Revised 7-Point Checklist. However, a biopsy of the suspicious mole or skin lesion is the definitive method to confirm melanoma.
This system is commonly employed to identify suspicious moles that may indicate melanoma:
This method provides a more structured approach for assessing lesions. It assigns points to major and minor criteria:
Any patient scoring three or more points on the checklist should be referred for further dermatological evaluation.
Melanoma is divided into stages using five Roman numerals (0 through IV) and up to four letters (A through D) that indicate a higher risk within each stage.
The stages of melanoma are determined mostly by specific details about the tumour and its growth that are tallied in a system called TNM where:
T stands for Tumour,
N stands for Nodes,
M stands for Metastasis.
Staging is important because cancer treatment options and prognoses are determined by stage.
Stage 0 (In Situ): Melanoma is confined to the epidermis, with no invasion of deeper layers.
Figure 1.18, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license
Stage I: Localized melanoma that is still thin, typically measuring 1 mm or less in thickness, confined to the skin.
Stage II: Thicker melanoma (greater than 1 mm) but still localized to the skin, with no lymph node involvement.
Figure 1.19, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license
Stage III: Melanoma has spread to nearby lymph nodes or tissues but has not yet reached distant organs.
Stage IV: Advanced melanoma with distant metastases, affecting organs such as the lungs, liver, brain, or bones.
Figure 1.20, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license
The treatment of melanoma depends on the stage of the disease:
Preventing melanoma revolves around minimizing UV radiation exposure: