Skin and Systemic Diseases Flashcards
What are the cutaneous features of thyroid disease?
- Dry skin (hypothyroidism)
- Thyroid dermopathy (Grave’s disease)
- Thyroid acropachy (Grave’s disease)
What are the cutaneous features of diabetes?
- Necrobiosis lipoidica (waxy appearance, usually yellow discolouration, often in shins, occasionally ulcerated and scars)
- Diabetic dermopathy (lots of inflammatory papules, some ulcerated)
- Scleroedema (infiltrated, spongy sensation in the skin)
- Leg ulcers
- Granuloma annulare (raised, circular lesions)
What are the cutaneous features of Cushing’s/steroid excess?
- Acne
- Striae
- Erythema
- Gynaecomastia
What are the cutaneous features of Addison’s/steroid insufficiency?
- Hyperpigmentation
- Acanthosis nigracans
What are the cutaneous features of sex hormone problems?
- Acne (testosterone/progesterone)
- Hirsuitism (testosterone)
- Dermatis (progesterone)
What are the cutaneous features of Vitamin B deficiency?
- Dermatitis (B6)
- Angular chelitis (B12)
- Pellagra (B3)
What are the cutaneous features of zinc deficiency?
- Acrodermatitis enteropathica (pustules, bullae, scaling, sacral and perioral distribution, inherited mutation in SLC39A which encodes an intestinal zinc transported)
What are the cutaneous features of Vitamin C deficiency?
- Punctate purpura/bruising
- Corkscrew spiral curly hairs
- Patchy hyperpigmentation
- Dry skin
- Dry hair
- Non-healing wounds
- Inflamed gums
What are the features of erythema nodosum?
- Causes include streptococcal infection, pregnancy/OCP, sarcoidosis, drug induced and bacterial/viral infection
- Red lumps commonly form on the shins and arms
What conditions are associated with pyoderma gangrenosum?
- IBD
- RA
- Myeloma
What cutaneous signs may indicate underlying systemic malignancy?
- Necrolytic migratory erythema (erythematous, scaly plaques associated with glucagonoma syndrome)
- Erythema gyratum repens (reddened concentric bands whorled woodgrain pattern associated with lung cancer)
- Acanthosis nigricans (smooth, velvet-like, hyperkeratotic plaques associeted with malignancy)
- Sweets syndrome (febrile, neutrophilic dermatoses of the skin associated with haematological malignancy)
- Sister Mary Joseph Nodule (associated with intraabdominal malignancy like ovarian cancer)
What hair and nail changes are associated with systemic disease?
- Alopecia areata hair loss (autoimmune)
- Hair thinning (B12, iron deficiency, lupus, hypothyroidism)
- Male pattern balding (androgen excess)
- Nail clubbing and nail fold telangiectasia
Definition of dermatophyte infection
- Superficial fungal infection of the skin or nails
- Caused by:
- Microsporum
- Epidermophyton
- Trichophyton
- Transmission through exposure to infected desquamated cells can occur by direct contact. Inoculation occurs through breaks in the skin where dermatophyte fungi enter, germinate, produce keratinases and invade the superficial skin layers. They require keratin for growth and so are restricted to the hair, skin and nails.
Signs and symptoms of dermatophyte infection
- Signs/symptoms include Hx of lesions, skin discomfort, scaling scalp lesions patchy alopecia, erythematous, scaling skin lesions with central clearing, dry palmer surface, vesicles and scaling of the hands, fissuring of the interdigital spaces and vesicles/pustules on the soles.
- Risk factors include exposure to infected people/animals/soil, exposure to fomites (i.e. hats, combs), chronic steroid use, HIV, diabetes, occlusive clothing, hot weather, obesity, hyperhidrosis, frequent public bathing areas while barefoot and recurrent trauma of the skin.
Investigation and management of deramtophyte infection
- Potassium hydroxide microscopy showing hyphae
- Topical therapy in non-severe cases involving skin alone (terbinafine cream)
- Systemic therapy in severe cases involving hair/nails (terbinafine or itraconazole)
- Complications include kerion (inflammatory, painful, boggy scalp mass) and bacterial infections
