Disorders of the extremities

Introduction

• Trauma
  • Injuries, burns, injections, decubitus, chillblains, neuropathic ulcers
• Infections
  • Viral: HSV, CMV
  • Bacterial: Gangrene, S. aureus, Strep. Pyogenes, osteomyelitis
  • Mycobacterial: Buruli ulcer (M. ulcerans), Bairnsdale ulcer, TB, leprosy
  • Fungal: Blastomycosis, coccidioidomycosis, mucormycosis
  • Spirochaetal: Syphilis
  • Parasitic: Leishmaniasis, amoebiasis, schistosomiasis
• Bites
  • Snakes, scorpions
• Metabolic
  • Diabetes, gout, calciphylaxis

Differential of extremity ulcers

• Vascular
  • Venous: Varicose veins, venous insufficiency
  • Arterial: HTN, arterial insufficiency, thrombosis, embolism
• Vasculitis
  • PAN, Behcet’s
• Malignancy
  • SCC, BCC, B or T cell lymphoma
• Haematological
  • Polycythaemia, sickle cell
• Dermatological
  • Bullous pemphigoid, necrobioisis lipoidica
• Hydroxyurea

Venous stasis dermatitis

• Dependent oedema, erythema and orange-brown hyperpigmentation
• Medial distal legs and pretibial leg are most frequently involved
• Bright weepy erythema +- ulceration in severe cases
• Pruritis is common
• Bacterial infection can complicate
  • Honey-coloured crusts and pustules suggest superinfection
  • Cellulitis +- lymphangitis

Venous stasis ulcers

• Usually within venous stasis dermatitis
• Medial and lateral malleoli and medial aspect of calf mostly
• Often aches with dependency
• Moist pink base, punched out appearance and orange-brown hyperpigmentation at borders
• Consider coexistant allergic contact dermatitis
• Treatment
  • Leg elevation and support stockings
  • Weeping eruptions require astringent compress
  • Low-medium potency topical steroid (hydrocortisone 2.5%) can be applied twice daily until erythema, scale and pruritis resolve
  • Oral antihistamines are useful for pruritis and nocturnal sedation
  • Antibiotics if superinfection suspected

Pyoderma gangrenosum

• Recurrent cutaneous, necrotising and non-infective ulceration mostly seen in women 30-50yo
• 50% associated with underlying disease (ie. IBD, arthritis and myeloproliferative disorders)
• Presentation
  • Superficial pustule or erythematous nodule that expands into large painful ulcer on lower limb with purulent base and irregular, undermined gunmetal coloured border
  • No associated lymphadenopathy
  • 50% occur at sites of trauma
  • Multiple surgical debridements with negative cultures raises suspicion
• Diagnosis of exclusion and clinical
• Treatment
  • Underlying disorder therapy + topical/systemic steroids
  • Sulfasalazine
  • Hyperbaric O2

Hand and foot dermatitis

• Differential
  • Allergic contact dermatitis
  • Irrititant contact dermatitis
  • Dyshidrosis
  • Atopic dermatitis
  • Dermatophytosis
  • Psoriasis
  • Lichen planus
  • Pityriasis rubra pilaris
  • Palmar plantar keratoderma
  • Autoimmune bullous disease
  • Dermatomyositis
  • Scabies

Dyshidrosis

• Aka vesicular hand dermatitis, dyshidrotic eczema, pompholyx
• Very small, pruritic vesicles on lateral and volar aspects of palms and soles
• Lack of erythema
• Vesicles form pustules over time and desquamate to leave scales

• Treatment
  • Cease all causative agents
  • Stop all creams
  • Restrict soaps, lotions
  • Protect hands and feet when working around house
  • Lubrication with petroleum jelly should be used frequently and liberally
  • N/saline soak for vesicular eruptions
  • High potency steroid ointment twice daily
  • Antihistamines for itch
  • Systemic glucocorticoids if particularly debilitating with prednisolone 1mg/kg PO daily with 2-3 week taper (taper prevents relapse)
  • Chronic cases may require ongoing high-potency topical steroid use
  • Treat superinfection (bacterial or herpetic)

Psoriasis

• Psoriasis vulgaris (plaque-type) may involve palms and soles or extend to elbows, knees, scalp, umbilicus or gluteal cleft
• Discrete plaques arise with erythema, scales and fissures
• Onycholysis (separation of nail plate from nail bed), nail pits, yellow discolouration of nails support diagnosis
• Pustular psoriasis is a variant with sterile pustules on instep of foot and thenar/hypothenar eminences of hands
• Can be definitively diagnosed by biopsy
• Treatment
  • High potency steroid ointments + petroleum jelly emollients
  • Tar solution is the long-term therapy via dermatologist

Psoriasis vulgaris

Pustular psoriasis

Erythema nodosum

• Inflammatory eruption of subcutaneous fat
• Causes
  • Idiopathic (50%)
  • Infectious
    • Fungal: Blastomycosis, coccidioidomycosis, histoplasmosis, dermatophyte
    • Bacterial: Strep, Campylobacter, Yersinia, TB, leprosy
    • Parasitic: Leishmaniasis, Toxoplasmosis
    • Viral: Herpes simplex, EBV
  • Pharmacological: Sulfonamides, OCP, Penicillin, vaccines
  • Sarcoidosis
  • IBD
  • Pregnancy
  • Behcet’s
  • Leukaemia/lymphoma

Erythema nodosum

• Clinical features
  • Tender, warm, ill-defined erythematous nodules mostly in pretibial area
  • Ulceration DOES NOT occur
• Clinically diagnosed
• Management
  • Analgesia, bed rest, elevation and NSAID’s
  • Treat underlying cause

Erythema nodosum

Lichen simplex chronicus

• Thickening of stratum corneum due to chronic friction and scratching
• Mostly ankles, lower extremities, neck, scrotum and vulva
• Intensely pruritic, well-demarcated plaques
• Chronic scratching results in lichenification
• Erythema, hyperpigmentation and excoriations are evident
• Scale is minimal
• High-potency topical steroid ointments should be applied 2-3 times daily to resolve itch-scratch cycle

Lichen simplex chronicus

Dermatitis herpetiformis

• Cutaneous manifestation of gluten sensitivity
• Vesicles, papules or urticarial plaques symmetrically distributed on extensor surfaces of extremities, back and buttocks
• Extremely pruritic with subsequent excoriations and lichenification
• 20% of patients will have clinical evidence of malabsorption

Vascular cutaneous conditions of extremities

• Purpura = Visible haemorrhage into skin or mucous membranes
• Petechiae = Small, flat lesions
• Ecchymoses = Large, flat lesions
• Palpable purpura = Raised
• Large ecchymoses generally indicate coagulation defects or trauma
• Petechiae often associated with thrombocytopaenia
• Palpable purpura and persistent, localised purpura suggest vasculitis

Vascular conditions

• Must rule out life-threats including thrombocytopaenia, vasculitis, platelet dysfunction, uraemia, over-anticoagulation, meningococcaemia, sepsis, DIC
• Also consider leukaemia, myeloproliferative disorders

Non-palpable purpura vascular conditions

• Non-palpable non-thrombocytopaenic
  • Cutaneous: Trauma, steroids, old age, sun exposure
  • Systemic: Uraemia, von Willebrand disease, scurvy, amyloid
• Non-palpable thrombocytopaenic
  • With splenomegaly
    • Normal marrow: Liver disease with portal hypertension, Myeloproliferative disorders, Lymphoproliferative disorders, Hypersplenism
    • Abnormal marrow: Leukaemia, lymphoma, myeloid metaplasia
  • Without splenomegaly
    • Normal marrow
      • Immune: ITP, drugs, infections, HIV
      • Non-immune: Vasculitis, sepsis, DIC, HUS, TTP
    • Abnormal marrow
      • Cytotoxics, aplasia, fibrosis, infiltration, alcohol, thiazides

Palpable purpura (vasculitis)

• PAN
• Leukocytoclastic
• HSP
• Infective: Meningococcaemia, gonoccocaemia, staphylococcus, rickettsial, enterovirus
• Embolic

Investigations in vasculitis

• FBC, UEC, LFT
• CRP, ESR
• HepB serology
• HepC serology
• ANA
• RF
• ANCA

Keratoderma blenorrhagica

• Component of Reiter syndrome in 15% of males
• Usually palmar plantar keratoderma but can spread to scrotum, scalp and trunk
• Vesiculo-pustular waxy lesions with yellow/brown colour
• C. trachomatis can be isolated from affected skin

Palm-sole rashes

• Coxsackie A16
• Secondary syphilis
• Janeway lesions of IE
• Kawasaki
• Measles
• Toxic shock syndrome
• Reactive arthritis
• Meningococcaemia
• SLE

Last Updated on October 13, 2021 by Andrew Crofton