Granulomatous Disorders Flashcards
Necrobiosis lipoidica clinical features
Well-demarcated waxy red-brown indurated plaques
Atrophic yellow centre
Glazed in appearance
Prominent telengiectasia in area of necrobiosis
Comedo-like plugs periphery of lesions
May ulcerate —> painful
Koebnerisation at sites of trauma may occur
Shins/pretibial
Most cases bilateral
Young adults/early middle age
Onset earlier in insulin-dependent diabetics than in non-insulin dependent diabetics/non-diabetics
Necrobiosis lipoidica associated diseases
Diabetes (diabetics with NLD are at higher risk of retinopathy, nephropathy than diabetics without NLD)
IBD - Ulcerative colitis, Crohn disease
After jejunal bypass surgery
Other granulomatous disorders - GA, Sarcoidosis
Necrobiosis lipoidica complications
Ulceration
Hypohidrosis/hypoaesthesia/anaesthesia
Risk of SCC in longstanding lesions (rare)
Necrobiosis lipoidica DDx
Pretibial myxoedema
Annular elastolytic giant cell granuloma
Sarcoidosis
Localised scleroderma/morphoea
Necrobiosis lipoidica investigations
Usually clinical diagnosis
Skin biopsy in atypical cases only
Annual screening for diabetes
Necrobiosis lipoidica management
Generally disappointing
No evidence that intervention alters course of disease
First line -
No treatment
Potent TCS under occlusive dressing, changed weekly
ILCS to active edge and perilesional area to limit progression (improves appearance, but atrophy usually remains)
Topical tacrolimus
Second line -
PUVA
UVA1 (mixed response)
Other (uncertain value) - PDT PDL may improve telengoectatic/red components - risk of ulceration Short course pred to stop disease activity Thalidomide Chloroquine Etanercept Pentoxifylline Clofazamine
Necrobiosis lipoidica histo
Normal/atrophic epidermis or ulcerated
Extensive Necrobiosis (degeneration of collagen) with surrounding histiocytes
Granulomas not well defined
Perivascular inflammatory infiltrate includes occasional eosinophils and plasma cells
Increased number small superficial blood vessels
Full thickness dermis, often extending to subcut fat
Fibrosis (old atrophic lesions)
Granuloma annulare clinical features
Annular indurated papules/plaques
Extremities
Slowly enlarge , eventually flatten/fade
Mostly asymptomatic
Reaction pattern to a variety of triggering factors
Uncommon on ears, periocular, palms, penis
Mucous membranes typically spared
4 Clinical variants, typically appear independently -
Localised
Generalised/disseminated - adults, may be itchy
Subcutaneous - children, may be tender
Perforating - adults, children, ethnic Hawaiians
Granuloma annulare associated diseases/triggers
Autoimmune thyroiditis (localised, generalised GA)
Hyperlipidaemia
Morphoea
Other granulomatous disorders I.e. necrobiosis lipoidica, sarcoidosis
Uveitis
Temporal arteritis
Diabetes (controversial)
Malignancy (older people with atypical GA I.e. painful lesions on palms/soles)
Infections/infestations - scabies, Hep B, TB, HPV, EBV, Lyme disease
Trauma - immunisations, tuberculin testing, bites, tattoos
UV exposure (seasonal GA, photodistributed GA)
PUVA (generalised GA)
Drug-induced - TNF-alpha inhibitors
Granuloma annulare histo
Necrobiotic (palisading) granulomas - foci of necrobiosis surrounded by palisading histiocytes, lymphocytes, multinucleated giant cells
- Superficial, mid dermis
- Granulomas separated by normal tissue
- Mucin present within foci of necrobiosis - Alcian blue pH 2.5, colloidal iron
- Eosinophils
- relative absence of plasma cells
Other variants - interstitial, sarcoidal/tuberculoid granulomas
Interstitial -
- no formed areas of necrobiosis
- Histiocytes, lymphocytes surround blood vessels and between collagen
- Collagen separated by mucin
Histological DDx -
Granulomatous MF
Interstitial granulomatous dermatitis
Interstitial drug reaction
Localised granuloma annulare variant
Most common variant
Ring of small smooth flesh-coloured/erythematous papules
Surface of skin over papules intact
No scaling
Annular lesions enlarge centrifugally before clearing
Solitary or multiple
Commonest on dorsal hands, knuckles, fingers, feet (but can occur anywhere)
Generalised/disseminated granuloma annulare variant
Adults, mostly female
May be itchy
Commonest form in HIV patients
Ill-defined
Skin coloured/erythematous macules, papules, plaques in annular pattern surrounding faintly violaceous centre
Trunk, limbs
? Sparing of vaccination sites
Subcutaneous granuloma annulare variant
Uncommon
Children
Nodules
Scalp, legs mainly pretibial region
May be tender
Perforating granuloma annulare variant
Uncommon
Adults, children
Ethnic Hawaiian
HIV
Localised/generalised papules develop yellowish centres —> discharge clear viscous fluid that dries to form a crust —> leaving hypo/hyperpigmented scar
Histo = transepidermal elimination of necrobiotic collagen
Granuloma annulare DDx
Annular lichen planus Erythema annulare centrifugum Erythema migrans of Lyme disease Tuberculides Tertiary syphilis Sarcoidosis
