Dermatology


Acute Generalized Exanthematous Pustulosis NEJM
  • NAIL CHANGES
    • Onychomycosis:
      • 3 distinct categories of fungus exists 
          • Filamentous Molds (Aspergillus, Mucor, Trichophyton, Fusarium)
          • Dimorphic Fungi (Intracellular infections)
            • Endemic mycoses (histoplasma, blastomyces, coccidoides)
            • Non-endemic (sporothrix)
          • Yeasts (Candida, Cryptococcus, Trichosporon)
      • Etiology of Fungal Nail Infection
          • Dermatophytes : A group of 3 types of Fungi that commonly causes skin, nail and hair infections
            • Obtain their nutrition from keratanized material (hence cause infection of keratanized structures i.e skin, nail, hair)
      1. Trichophyton rubrum (80-90%); , T. mentagrophytes
      2. Epidermophyton
      3. Microsporum
          • Non-dermatophytes: 
            • Yeasts: Mostly Candida, 
            • At times Saprophytes, Fusarium (may be seen in histology and not in culture)
      • Type NEJM 2009
        • Distolateral Subungal Onychomycosis
        • Superficial White Onychomycosis
        • Proximal White Onychomycosis
      • DDx: BMJ 2014
        • Psoriasis
        • Trauma
        • Lichen Planus
        • Periungal Sq. Cell Ca / Bowens Disease 
        • Yellow-Nail Syndrome
        • Malignant Melanoma
        • Mucoid cyst
        • Alopecia areata
      • Physical Exam:
        • Friable nail plate and nail spikes are very typical of fungal infection due to how fungus invades nail
          • This is visible as Hyperkeratotic bands that progress proximally
      • Diagnosis
        • Ideally site is to be cleaned with 70% Ethanol before sample collection, and sample material is send for 
          • Microscopy
          • Culture
      • Treatment: BMJ 2014
        • Topical
          • Indications: 
            • 50 % Involvement of the distal nail plate with 
            • Lack of matrix involvement
            • 3 or 4 nails involved
            • Early Distolateral disease
          • Amorolfine for 12 months (Cure rate of around 47 % at 48 weeks)
          • Ciclopirox
          • Others Less Commonly Used
            • Tioconazole
            • Efinaconazole (not yet approved in US)

        • Systemic
          • First Line
            • Itraconazole
              • 200 mg / day; 6 wks for Finger Nails; 12 wks for Toe Nails
              • 400 mg / day for 1 week a month
                • 2 months for Finger Nails
                • 3 months for toe nails
              • Contraindications: Chronic or Active Liver Disease, Heart Conditions, BZD use
            • Terbinafine
              • 250 mg / day 
                • 6 wks for finger nails
                • 12 - 16 wks for toe nails
              • Contraindication: Chronic or Active Liver Disease
          • Off label
            • Fluconazole
            • Griseofulvin
    • Nail Infection: Also, see skin infection in Infectious Disease
          • pemphigoid
          • dermatitis Herpetiformis
          • Insect Bite
          • Contact dermatitis
        • Systemic Causess
          • Cholestasis (Primary Biliary Cirrhosis)
          • Chronic Kidney Disease
          • Myeloproliferative Disorder
          • Hyperthyroidism
          • HD (it can be the first manifestation at times)
          • Cutaneous T-Cell Lymphoma
          • HIV
          • PCRV
        • Neuropathic Cause
          • Notalgia Paresthetica (Distinctive itch of the upper back)
          • Brachioradial Pruritus (probably caused by spinal nerve impingement
          • Postherpetic Itch
        • Psychogenic Cause
          • OCD
          • Delusion of parasitosis
          • Substance abuse
        • Pruritus of undetermined origin
      • Clinical Manifestation
        • Dermatological
          • Primary lesion
          • Secondary skin lesion (skin lesion does not rule out non-dermatological cause)
            • Excoriations
            • Non-specific Dermatitis
            • Prurigo Nodularis
            • Lichen Simplex Chronicus
        • Aypical symptoms are common (do not jump to diagnose psychogenic cause)
      • Treatment
        • Topical Therapy
          • Emollients and Soaps
          • Anesthetics
          • Coolants
          • Glucocorticoids
          • Other Agents
        • Systemic Therapy
          • Anti-histamines
            • Diphenhydramine hydrochloride (25, 50 mg tablets or capsules): 25-50 mg nightly or every 6 hours as needed.
            • Hydroxyzine (10, 25 mg tablets): 10-25 mg every 6 hours as needed.
            • Cetirizine hydrochloride (5,10 mg tablets): 5-10 mg per day.
            • Loratadine (10 mg tablets and RediTabs): 10 mg tablet or RediTab once daily.
          • Neuroactive Medications
          • Antidepressants
          • Opiad agonits and Anta-gonists
        • Chronic Pruritus NEJM 2013
Lesson to Learn:
Secondary skin lesions can make the diagnosis difficult
Biopsy can be false negative. 
Skin scraping and viewing under microscope will help confirm the diagnosis. 
Scabies NEJM 2016

Erythema Migrans DDx: Table 2 of Lyme Disease NEJM 2014 
  • Single EM Lesion
    • Lyme Disease Early EM
      • Erythema migrans usually begins as a small erythematous papule or macule that appears at the site of the tick bite 1 to 2 weeks later (range, 3 to 32 days) and subsequently enlarges.
      • may be asymptom- attic, mildly pruritic, or, in rare cases, painful; 
      • if untreated, lesions may become 61 cm (2 ft) in diameter or larger and may last for 3 to 4 weeks before resolving 
      • Bull's eye appearance is classic but  2/3rd of single EM lesion are either uniformly erythematous or have enhanced central erythema without clearing around it
    • Nummular Eczema
    • Tinea
    • Granuloma Annulare
    • Cellulitis
    • Insect bite
    • Spider bite
    • Hypersensitivity to tick bite 
  • Multiple EM lesion
    • Early disseminated Lyme Disease
    • Erythema Multiforme
    • Urticaria 

Clinical Guidelines: Please look for clinical guidelines in respective heading with yellow highlight like this

Common Rash

Intertrigo and Common Secondary Skin Infections AAFP 2005

Acneform Lesion
Diagnosis and management of hidradenitis suppurativa BMJ 2013
Acne vulgaris BMJ 2013
Rosacea NEJM 2005
Hidradenitis Suppurativa NEJM 2012
Nail Infections (Skin Infections : please see Infectious Disease)
Common Neoplasm
Cutaneous Neoplasm Lancet 2013

Dysplastic Nevi NEJM 2003
Skin Cancers after Organ Transplantation NEJM 2003
Melanoma NEJM 2006
Management of Cutaneous Melanoma NEJM 2004
Basal-Cell Carcinoma NEJM 2005
The Pathogenesis of Mycosis Fungoides NEJM 2004
Sentinel-Lymph-Node Biopsy for Cutaneous Melanoma NEJM 2011

Cutaneous  Manifestation of Internal Disease
Dermatological Emergencies
Nail Disorders
Alopecia
Alopecia Areata NEJM 2012
Hair Loss in Women NEJM 2007
Foot / Leg Ulcers 
Current Management of Acute Cutaneous Wounds NEJM 2008
Miscellaneous

Recent Publications in Dermatology


Pharmacology in Dermatology
Acne, Rosacea and Psoriasis