🏥 Stations

🧠 Qbank

📖 Book

😃 More

💳 Pricing

🔒 Dashboard

📖 OSCE Learning

🔒 OSCE Stations

🔒 Qbank

🔐 Membership
Share your insights

Help us by sharing what content you've recieved in your exams


Skin lesion

Specialties > Dermatology

Differential Diagnosis Schema 🧠

Benign Skin Lesions

  • Seborrheic keratosis: Warty, pigmented, and stuck-on appearance, commonly found on the trunk and face.
  • Lipoma: Soft, mobile, and painless subcutaneous nodules, often found on the trunk and limbs.
  • Dermatofibroma: Firm, hyperpigmented nodules with a dimple sign, commonly found on the lower legs.
  • Cherry angioma: Small, red to purple papules that blanch with pressure, commonly found on the trunk.
  • Epidermoid cyst: Central punctum, filled with keratin, commonly found on the face, neck, and trunk.
  • Actinic keratosis: Rough, scaly patches, precancerous lesions commonly found on sun-exposed areas.
  • Milia: Small, white, cystic lesions often found on the face, particularly around the eyes.
  • Molluscum contagiosum: Small, umbilicated papules caused by a poxvirus, commonly seen in children.

Malignant and Pre-Malignant Lesions

  • Basal cell carcinoma: Pearly papule with rolled edges and telangiectasia, often found on sun-exposed areas.
  • Squamous cell carcinoma: Scaly, ulcerated, or crusted lesions, often arising from actinic keratoses, found on sun-exposed areas.
  • Melanoma: Asymmetric, irregularly bordered, and variably pigmented lesion with a diameter greater than 6mm, may arise from a mole.
  • Bowen’s disease: In situ squamous cell carcinoma, presents as a persistent, scaly, and erythematous patch.
  • Keratoacanthoma: Rapidly growing, dome-shaped nodule with central keratin plug, may resolve spontaneously or develop into squamous cell carcinoma.
  • Lentigo maligna: A slow-growing, flat, pigmented lesion with irregular borders, often on the face of elderly individuals.
  • Kaposi’s sarcoma: Purplish, red, or brown plaques or nodules, often seen in immunocompromised individuals.
  • Cutaneous T-cell lymphoma (Mycosis fungoides): Patches, plaques, and nodules, often with pruritus, may mimic eczema or psoriasis initially.
  • Paget’s disease of the breast: Eczematous changes around the nipple, associated with underlying breast carcinoma.
  • Merkel cell carcinoma: Fast-growing, firm, non-tender, red or violet nodules, usually on sun-exposed areas.
  • Sebaceous carcinoma: Rare, aggressive tumor, often presents as a painless nodule on the eyelid.
  • Neurofibromatosis: Café-au-lait spots and neurofibromas, associated with an increased risk of malignancy.
  • Dermatofibrosarcoma protuberans: A rare, slow-growing soft tissue sarcoma that may recur locally after excision.

Key Points in History 🥼

History of Presenting Complaint

  • Onset: Ask about the duration of the lesion and whether it has changed in size, shape, or color.
  • Symptoms: Inquire about any associated symptoms such as itching, bleeding, or pain.
  • Growth pattern: Determine if the lesion has grown rapidly or slowly, and whether it has been stable or evolving.
  • Precipitating factors: Ask about any recent trauma, sun exposure, or infections that could have contributed to the lesion’s appearance.
  • Previous treatment: Inquire about any previous treatments or interventions and their outcomes.
  • Location: Assess the lesion’s location on the body, particularly if it’s in a sun-exposed area.
  • Number of lesions: Note whether the lesion is solitary or if there are multiple lesions, which may suggest a systemic condition.
  • Past history of skin cancer: Document any previous history of skin cancers or pre-malignant lesions.
  • Family history: Ask about a family history of skin cancers, particularly melanoma.
  • Sun exposure: Explore the patient’s history of sun exposure, including tanning habits and use of sunscreen.
  • Immunosuppression: Inquire about any immunosuppressive conditions or medications, which increase the risk of malignancy.
  • Occupation: Consider the patient’s occupation and whether it involves significant sun exposure or contact with carcinogens.
  • Skin type: Note the patient’s skin type, as fair-skinned individuals are at higher risk for skin cancer.
  • Systemic symptoms: Investigate the presence of systemic symptoms like fever, weight loss, or lymphadenopathy, which may suggest a malignant process.
  • Cosmetic concerns: Discuss the patient’s concerns about the appearance of the lesion and any impact on quality of life.

Background

  • Medical history: Review for chronic conditions such as psoriasis, eczema, or other dermatological diseases.
  • Medication history: Consider medications that may affect skin health, including immunosuppressants or photosensitizing drugs.
  • Allergies: Inquire about any history of allergic reactions, particularly to topical agents or skincare products.
  • Surgical history: Ask about any previous skin biopsies, excisions, or treatments for skin lesions.
  • Family history: Document any family history of skin conditions, particularly those with a genetic component.
  • Social history: Explore lifestyle factors such as smoking, alcohol use, and occupational exposure to chemicals or irritants.
  • Travel history: Consider travel to areas with high sun exposure or regions where infectious causes of skin lesions are more prevalent.
  • Psychosocial factors: Assess the impact of the skin lesion on the patient’s mental health, self-esteem, and social interactions.
  • Dietary habits: Evaluate the patient’s diet, particularly if there is a suspicion of nutritional deficiencies that could affect skin health.
  • Occupational history: Investigate if the patient’s work involves exposure to physical or chemical hazards that could precipitate skin lesions.
  • Sun protection measures: Ask about the use of sun protection measures, including sunscreen, protective clothing, and seeking shade.
  • Sexual history: Consider sexually transmitted infections (STIs) that may present with skin lesions, particularly in the genital area.
  • Environmental exposures: Explore any contact with plants, animals, or chemicals that could contribute to skin lesions.
  • Vaccination status: Particularly important in patients with possible infectious causes of skin lesions (e.g., HPV, molluscum contagiosum).
  • Immunization status: Consider the impact of immune status on the development and persistence of skin lesions.
  • Nutritional status: Poor nutrition can contribute to poor skin health and delayed healing of lesions.
  • Previous imaging or investigations: Review any prior investigations or imaging studies related to the skin lesion.
  • Psychosocial functioning: Assess the impact of the skin lesion on the patient’s daily life, including relationships, work, and leisure activities.
  • Recent changes: Explore any recent life changes, stressors, or trauma that may have contributed to the onset or worsening of skin lesions.
  • Safety planning: Discuss safety plans related to skin lesion management, particularly if excision or other interventions are planned.

Possible Investigations 🌡️

Initial Investigations

  • Dermatoscopy: Non-invasive technique to examine skin lesions with magnification, helping to differentiate benign from malignant lesions.
  • Skin biopsy: Excisional, incisional, punch, or shave biopsy for histopathological examination to confirm diagnosis.
  • Wood’s lamp examination: Useful in diagnosing pigmentary changes and fungal infections.
  • Swab for microbiology: If infection is suspected, take a swab for bacterial, viral, or fungal culture.
  • Blood tests: FBC, U&E, LFTs, and CRP to assess for systemic involvement or underlying conditions contributing to the skin lesion.
  • Allergy testing: Consider patch testing if allergic contact dermatitis is suspected.
  • Immunohistochemistry: To assess for specific markers, particularly in suspected malignancies.
  • Imaging: Ultrasound, MRI, or CT scans may be indicated if deeper tissue involvement or metastasis is suspected.
  • Molecular testing: In certain cases, genetic or molecular tests may be required, particularly in the diagnosis of melanoma or other skin cancers.
  • Lymph node biopsy: If regional lymphadenopathy is present, particularly in suspected melanoma or squamous cell carcinoma.
  • Serology: To assess for underlying infectious causes, particularly in the context of viral or systemic bacterial infections.
  • Photographic documentation: For monitoring changes in the lesion over time, particularly for pre-malignant or early malignant lesions.
  • Autoimmune panel: If an autoimmune etiology is suspected (e.g., lupus, dermatomyositis).
  • HIV testing: Consider in patients with unexplained skin lesions and risk factors for HIV infection.
  • Skin scraping: For suspected scabies or other parasitic infections, skin scrapings can be taken for microscopy.
  • Direct immunofluorescence: Useful in diagnosing blistering disorders and connective tissue diseases.
  • Referral to dermatology: For specialized assessment and management, particularly in complex or atypical cases.
  • Multidisciplinary team (MDT) discussion: In cases of suspected malignancy, involvement of an MDT for treatment planning is crucial.
  • Repeat biopsy: May be necessary if initial biopsy results are inconclusive or if the lesion changes.
  • Holistic assessment: Consideration of the patient’s overall health and well-being, including psychosocial factors.

No comments yet 😉

Leave a Reply

Dermatology