Dermatology Cases PDF

## Scabies - **Pathogen:** Sarcoptes scabiei. - **Transmission:** Highly contagious and transmitted via direct physical (skin-to-skin or sexual) contact. - **Pathophysiology:** The excretions of the mites and their decomposing bodies contain antigens which cause an immunological response. - **Sign...

## Scabies - **Pathogen:** Sarcoptes scabiei. - **Transmission:** Highly contagious and transmitted via direct physical (skin-to-skin or sexual) contact. - **Pathophysiology:** The excretions of the mites and their decomposing bodies contain antigens which cause an immunological response. - **Signs and symptoms:** A pimple-like rash, burrows, and intense itching that worsens at night. - **Predilection sites:** Inter digital folds Male genitalia. - **Diagnosis:** Requires direct visualization of the mites or their eggs or feces using a dermatoscope. - **Treatment:** - Topical application of a scabicidal agent permethrin 5% lotion - Oral ivermectin - **Prevention** - Wash all textiles (e.g., clothing and bedding) - All contacts within the household should be treated for scabies infestation even if asymptomatic. ## Case 1: 4-Year-Old Boy - **Symptoms:** A 4-year-old boy presents with a pruritic rash on his hands and feet for the past 2 weeks. The rash is intensely pruritic, especially at night. He has not had fever, headache, or diarrhea. - **History:** The boy's mother has a history of eczema. - **Physical Exam:** A maculopapular rash with linear tracks affecting the interdigital spaces of the fingers and toes. The remainder of the examination shows no abnormalities. - **Diagnosis:** Scabies ## Case 2: 26-Year-Old Man - **Symptoms:** A previously healthy 26-year-old man presents with a 1-week history of pruritic rash. Initially, he noticed a set of small, red "bumps" in a linear pattern along his arm. Although these started to recede after a few days, he found another set of similar lesions in clusters on his back yesterday morning. The itching is worse at night. His roommates have also developed similar rashes since moving into their new apartment in San Francisco 2 weeks ago. - **History:** There are no pets at home. - **Physical Exam:** Temperature is 36.8°C (98.4°F), pulse is 70/min, and blood pressure is 108/70 mm Hg. A photograph of the patient's rash is shown. The remainder of the physical examination shows no abnormalities. - **Diagnosis:** Scabies. - **Confirmation:** Direct visualization of the mites or their eggs or feces using a dermatoscope. - **Treatment:** Topical permethrin is the first-line treatment. - **Prevention:** Prophylactic treatment of all close contacts. ## Measles - **Pathogen:** Paramyxovirus, an RNA virus. - **Signs and symptoms:** Coryza, Cough, and Conjunctivitis, Koplik spots (pathognomonic), Fever, enanthem of the buccal mucosa, Erythematous maculopapular rash (begins behind the ears and disseminates to the rest of the body towards the feet; palm and sole involvement is rare). - **Diagnosis:** Gold standard: detection of Measles-specific IgM antibodies or PCR. - **Treatment:** Symptomatic treatment and Vitamin A supplementation reduces morbidity and mortality. - **Prevention:** Live attenuated vaccines. - **Isolation:** Isolate patients for 4 days from the onset of rash (longer if immunocompromised). - **Hospitalized patients:** Initiate airborne precautions. ## Case 3: 6-Year-Old Boy - **Symptoms:** A previously healthy 6-year-old boy is brought to the physician because of a 3-day history of progressive rash. The rash started on his face, now involves the entire body, and is not itchy. For the past week, he has had a cough and a runny nose. - **History:** He is visiting from the Philippines with his family. He is in first grade and spends his afternoons at an after-school child care program. Immunization records are not available. - **Physical exam:** Temperature is 39.5°C (103°F), pulse is 115/min, and blood pressure is 105/66 mm Hg. Examination shows generalized lymphadenopathy. There is an erythematous maculopapular, blanching, and partially confluent exanthem on his entire body. The remainder of the examination shows no abnormalities. - **Diagnosis:** Measles - **Confirmation:** Detection of Measles-specific IgM antibodies or PCR. ## Case 4: 11-Year-Old Boy - **Symptoms:** A previously healthy 11-year-old boy is brought to the emergency department because of a 3-day history of fever, cough, and a runny nose. During this period, he has also had pink, itchy eyes. - **History:** The patient emigrated from Syria 2 weeks ago. His parents died 6 months ago. He has not yet received any routine childhood vaccinations. He lives at a foster home with ten other refugees; two have similar symptoms. He appears anxious and is sweating. - **Physical Exam:** Temperature is 39.2°C (102.5°F), pulse is 100/min, respirations are 20/min, and blood pressure is 125/75 mm Hg. Examination shows conjunctivitis of both eyes. There are multiple, 2-mm-sized, bluish-gray papules with an erythematous rim on the buccal mucosa and the soft palate. - **Diagnosis:** Measles - **Complications:** Increased risk for encephalitis ## Case 5: 5-Year-Old Boy - **Symptoms:** A 5-year-old boy is brought to the emergency department for evaluation of a progressive rash that started 2 days ago. The rash began on the face and progressed to the trunk and extremities. Over the past week, he has had a runny nose, a cough, and red, crusty eyes. - **History:** He immigrated with his family from Turkey 3 months ago. His father and his older brother have Behçet disease. Immunization records are unavailable. - **Physical Exam:** The patient appears irritable and cries during the examination. His temperature is 40.0°C (104°F). Examination shows generalized lymphadenopathy and dry mucous membranes. Skin turgor is decreased. There is a blanching, partially confluent erythematous maculopapular exanthem. Examination of the oral cavity shows two 5-mm aphthous ulcers at the base of the tongue. - **Diagnosis:** Measles - **Next steps:** Obtain a viral culture. ## Tinea Versicolor - **Pathogen:** *Malassezia furfur* - **Pathophysiology:** *Malassezia furfur* damages melanocytes, leading to hypopigmentation. An inflammatory response to the pathogen may cause hyperpigmentation - **Signs and symptoms:** Colors vary (hypopigmented, hyperpigmented, or erythematous skin lesions). Common sites are the trunk and chest. - **Diagnosis:** Clinical diagnosis - **Confirmation:** Potassium hydroxide (KOH) preparation reveals a spaghetti-and-meatballs pattern. - **Treatment:** - Topical antifungals (first-line therapy): Selenium sulfide or zinc pyrithione in form of lotion or shampoo. - Oral antifungals (reserved for infections that are severe, widespread, or unresponsive to topical therapy): Oral fluconazole ## Case 6: 21-Year-Old Man - **Symptoms:** A 21-year-old man comes to the physician because of pruritus and a hypopigmented rash on his upper body for 5 days. He first noticed the symptoms after returning from a business trip last week in the Bahamas. The rash initially started as a single lesion on his upper back but since then has extended to his shoulders - **History:** The patient has a history of type 1 diabetes mellitus controlled with an insulin pump. He has been sexually active with three female partners over the past year and uses condoms inconsistently. - **Physical exam:** Temperature is 37.2°C (99°F), pulse is 78/min, and blood pressure is 130/84 mm Hg. A photograph of the rash is shown. One month ago, his hemoglobin A1C was 7.8%. - **Diagnosis:** Tinea Versicolor - **Confirmation:** Potassium hydroxide preparation is conducted on a skin scraping of the hypopigmented area. Microscopy of the preparation shows long hyphae among clusters of yeast cells. - **Treatment:** Topical antifungals (Selenium sulfide) or Oral antifungals (Oral fluconazole) ## Case 7: 13-Year-Old Boy - **Symptoms:** A 13-year-old boy is brought to the physician because of a 5-day history of a rash on his chest and back. His mother initially noticed only a few lesions on his back, but since then the rash has spread to his chest. - **History:** His family returned from a trip to the Caribbean 2 weeks ago. His mother started using a new laundry detergent 8 days ago. He has type 1 diabetes mellitus controlled with insulin. His mother has Hashimoto thyroiditis and his brother has severe facial acne. - **Physical exam:** Temperature is 37.2°C (99°F), pulse is 81/min, and blood pressure is 115/74 mm Hg. Examination of the skin shows multiple, nontender, round, white macules on the chest and trunk. There is fine scaling when the lesions are scraped with a spatula. There are no excoriation marks. The remainder of the examination shows no abnormalities. - **Diagnosis:** Tinea Versicolor - **Confirmation:** Potassium hydroxide (KOH) preparation - **Treatment:** Topical antifungals (Selenium sulfide) or Oral antifungals (Oral fluconazole) ## Pityriasis Rosea - **Etiology:** Idiopathic. A viral etiology (HHV 6 and 7) is suspected. - **Signs and symptoms:** Preceded by prodromal flu-like illness, multiple, oval, scaly papules distributed in a classic Christmas tree pattern on the trunk with itching. The lesions typically disappear within two months, often causing postinflammatory hyperpigmentation or hypopigmentation. - **Diagnosis:** Usually a clinical diagnosis. Laboratory tests may be considered if the diagnosis is uncertain. - **Confirmation:** KOH preparation: to exclude tinea. RPR or VDRL: to exclude secondary syphilis. - **Treatment:** Spontaneous resolution within 6-8 weeks. ## Case 8: 10-Year-Old Girl - **Symptoms:** A 10-year-old girl is brought to the physician by her mother because of a 10-day history of a pruritic rash. The mother reports that she initially noticed a single round lesion on the child's upper abdomen that gradually increased in size; smaller lesions have since spread over her trunk, neck, and both arms. - **History:** The child also had a fever, sore throat, and malaise a week before the onset of the rash. The child and her family recently went for a picnic in the woods around their house, but the mother does not recall seeing any ticks on the child. She has no significant past medical history and does not take any medications. - **Physical Exam:** Temperature is 36.8 °C (98.4 °F), pulse is 86/min, and blood pressure is 90/60 mm Hg. Physical examination shows the findings in the photograph. - **Diagnosis:** Pityriasis Rosea ## Skin Cancer - **Most important skin cancers:** BCC, SCC, MELANOMA. - **Most common type of skin cancer:** Basal cell carcinoma. ### Common Key Words - Painless lesion - Hx of Sun exposure (come from Australia, summer, outdoor job ...) - Increase in size for months. ### Basal Cell Carcinoma - **Signs and symptoms:** - Nodular lesion with central ulceration. - Non tender, firm, pearly telangiectatic papules. - Most lesions appear on the face or other sun-exposed areas. - **Diagnosis:** Excisional biopsy, shave biopsy or punch biopsy. - **Treatment:** - If on the trunk or extremities: surgical excision with 3-5 mm margins. - Lesions on the face: Surgical excision (Mohs Micrographic Surgery). ## Case 9: 48-Year-Old Woman - **Symptoms:** A 48-year-old woman comes to the physician because of a small swelling on her neck. She has worked outdoors her entire life. This swelling has been present for the past 6 months and is slowy enlarging. - **Physical exam:** On examination, there is a small nodular lesion with central ulceration that is firm, nontender, pearly, and indurated. - **Diagnosis:** Basal Cell Carcinoma ### Squamous Cell Carcinoma - **Signs and symptoms:** - Common in patients with: history of transplant, on chronic immunosuppressive therapy, ionizing radiation, and burn injuries. - Nodular lesion with intermittent bleeding and itching. - The lesions often become keratinized (with a thickened, rough surface). - Lesions can ulcerate with crusting and bleeding. - Perineural invasion is a feature of SCC → numbness, paresthesia and itching. - **Diagnosis:** Shave biopsy, which may show keratin pearls and full-thickness atypical keratinocytes with invasion into the dermis. - **Treatment:** Surgical excision or Mohs surgery (very thin slices are excised and examined with a microscope via frozen section, ideally used for cosmetically sensitive areas such as face and distal extremities). Lesions with high metastatic potential may need radiation or chemotherapy. ## Case 10: 65-Year-Old Man - **Symptoms:** A 65-year-old man comes to the office due to a nonhealing ulcer on the left upper extremity. For the last 2 months, he has had an enlarging ulcerated lesion, with intermittent bleeding and itching. - **History:** He does not recall any injury prior to the onset of symptoms. He has good appetite and reports no weight loss. There is no fever, dyspnea, or cough. He does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. - **Physical exam:** Physical examination of the lesion is shown in the image below. The remainder of the examination is unremarkable. - **Diagnosis:** Squamous Cell Carcinoma ### Malignant Melanoma - **Signs and symptoms:** ABCDE criteria - Asymmetry - Border (irregular border with indistinct margins) - Color (variegated pigmentation within the same lesion) - Diameter > 6 mm - Evolving (a lesion that changes in size, shape, or color over time) - If the patient has multiple nevi, a lesion that is significantly different from patient's other moles also warrants increased suspicion ("Ugly duckling" sign) - **Diagnosis:** Skin biopsy - **Treatment:** Wide local excision (should be performed with surgical margins determined by the Breslow depth) - **Prognosis:** Tumor thickness, as determined from the Breslow thickness. ## Case 11: 63-Year-Old Man - **Symptoms:** A 63-year-old man comes to the physician for the evaluation of a skin lesion on his chest. He first noticed the lesion 2 months ago and thinks that it has increased in size since then. The lesion is not painful or pruritic - **History:** The patient otherwise feels well. He has type 2 diabetes mellitus, hypercholesterolemia, and glaucoma. - **Diagnosis:** Malignant Melanoma.