These tutorials are particularly directed at third and fourth year registrars.They are meant to give you a broad introduction to clinical dermatology particularly aspects of differential diagnosis. They will use online atlases ,PubMed and eMedicine websites as resource materials as well as the cases in the Dermconsult website itself. The format is based on one used by Ken Paver some years ago.
Topics covered in this tutorial
1. Ulcers
2.Lymphadenopathy
Questions on the following conditions.
Epithelioma cuniculatum
Atrophe blanche
Pyoderma gangrenosum
Calcinosis cutis
Dercum's disease
Dermatitis artefacta
Bazin's disease
Orf
Behcet's syndrome
Herpangina and Hand Foot and Mouth disease
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ULCERS
The differential diagnosis of ulcers is obviously very wide. The site of the ulcer, speed of onset and the degree of undermining plus the nature of the surrounding skin usually allow you to narrow down that differential. An all encompassing approach is to use the acronym AUST TAIL where A is arterial, U is undermined, S is surrounding skin, T is trauma. The other T is tumours, A is anaesthesia, I is infection and L is lymphadenopathy.
ARTERIAL - can be subdivided into A, B, C, D and E. A is arteritis, particularly Wegener's, polyarteritis nodosa and giant cell arteritis. B is blood and bites, particularly cholesterol emboli, dysproteinemias, disseminated intravascular coagulation and thalassemia. C is cold. D is drugs particularly Ergot, Halogens and Methotrexate and E is Emboli.
UNDERMINED - particularly pyoderma gangrenosum and decubitus ulcers.
SURROUNDING - particularly venous stasis, necrobiosis lipoidica, radiation.
TUMOURS - All types, plus calcinosis cutis.
TRAUMA - particularly dermatitis artefacta, heat, cold and electricity.
ANAESTHESIA - particularly trophic ulcers and infection, for example, leprosy. Diabetic ulcers are both neuropathic and ischaemic.
INFECTION - particularly anthrax, atypical mycobacteria, lymphogranuloma venereum, syphilis, Chancroid
PYODERMA GANGRENOSUM
It is important to know the way this lesion can start. It may just be a reddish nodule or a pustule, or sometimes a haemorrhagic bulla that breaks down to give the characteristic undermined edges. The lesion is usually of rapid onset and painful. It may be associated with recent surgery. There is usually history of underlying disease and this can be followed up in the reference below. Note that patients and their doctors often diagnose the initial lesion of Pyoderma gangrenosum as a spider bite! Consider factitial ulcers in the differential.
eMedicine-Pyoderma gangrenosum
GSA-Pyoderma Gangrenosum Late Scarred Pyoderma gangrenosum
Verrucous annular ulcerated hip plaques
Question What underlying conditions are associated with pyoderma gangrenosum?
The photos below are of pyoderma gangrenosum These lesions are rapidly enlarging and painful. Mycobacterium ulcerans can also be undermined but is slower to evolve and painless.
EPITHELIOMA CUNICULATUM
The word Cuniculatum refers to a rabbit burrow. This lesion may present as a plantar wart but do not touch it. It is really a form of squamous cell skin cancer, often verrucous in nature. Radiotherapy for these lesions is not usually recommended as it may induce anaplastic transformation. Lymph node metastasis is rare. Note that a deep incisional biopsy is important to avoid the mistake of diagnosing this as a verruca.
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You do not get venous ulceration on the sole of the foot. An ulcer there is either arterial or neuropathic.
eMedicine-Verrucous carcinoma
An ulcerating verrucous plaque on the foot
The photo below is verrucous carcinoma of the buccal mucosae
CALCINOSIS CUTIS
Calcinosis Cutis is divided into four forms.
- Dystrophic calcinosis where serum calcium and phosphorus levels are normal.
- Metastatic calcification, where serum levels of calcium and phosphate are raised, for example hyperparathyroidism.
- Iatrogenic and traumatic calcinosis which is seen with medical procedures, such as leakage of infusions or injections of calcium with local elevated calcium levels, and
- Idiopathic calcinosis cutis, with a normal serum calcium.
An interesting point to note of miliary osteomas of the face in women is that if they have taken tetracycline, because of preceding acne, these osteomas will be pigmented and may fluoresce with ultraviolet light.
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eMedicine-Calcinosis cutis
GSA Calcinosis Cutis
Off-Centre Fold
Question-DIFFERENTIATE THE FOLLOWING
Cutaneous calculus,osteoma cutis and pilomatrixoma.
Cutaneous calculus - It is yellow white, single, often on the face of children and it is hard.
Osteoma cutis - Very small grouped bone in skin and is often picked up in x-rays.
Pilomatrixoma - It is usually on the forehead, it may be lobulated and again it is hard.
| Feature | Cutaneous calculus (Calcinosis cutis) | Osteoma cutis | Pilomatrixoma |
|---|---|---|---|
| Primary process | Calcium salt deposition without true bone | True bone formation (ossification) in skin | Benign hair matrix tumor with calcification/ossification |
| Main tissue change | Amorphous/granular calcium in dermis/subcutis | Mature bone trabeculae ± marrow in dermis | Basaloid and shadow cells with calcification |
| Common sites | Variable; often at damaged skin, periarticular or acral | Face and scalp, sometimes scars or neoplasms | Head, neck, upper extremities in children/young adults |
| Key associations | Connective tissue disease, renal failure, trauma, iatrogenic | Genetic ossification disorders, acne scars, inflammatory dermatoses, tumors | Wnt/β‑catenin pathway mutations, some genetic syndromes |
| Typical age | Any, often adults with systemic disease | Variable; miliary facial form often in adults with acne history | Mostly first–second decades |
| Management focus | Treat underlying cause ± remove lesions | Usually cosmetic excision if needed | Complete excision; low recurrence |
The photo below is cutaneous calcinosis
BAZIN'S DISEASE OR ERYTHEMA INDURATUM
Erythema Induratum usually occurs in middle aged women on the posterior lower calf with indurated, sometimes ulcerated, areas and surrounding acrocyanosis. Most of the damage in this condition is occurring in subcutaneous fat which shows a lobular panniculitis with fat necrosis. Granulomatous inflammation occurs in about 60% of the cases. You should do a Gold quantiferon test to see if the patient has occult TB that will need treated for this condition to settle. Vasculitis also occurs.
BAZIN'S DISEASE OR ERYTHEMA INDURATUM
Erythema Induratum usually occurs in middle aged women on the posterior lower calf with indurated, sometimes ulcerated, areas and surrounding acrocyanosis. Most of the damage in this condition is occurring in subcutaneous fat which shows a lobular panniculitis with fat necrosis. Granulomatous inflammation occurs in about 60% of the cases. You should do a Gold quantiferon test to see if the patient has occult TB that will need treated for this condition to settle. Vasculitis also occurs.
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eMedicine-Bazin's disease-Erythema induratum
Global Skin Atlas-Erythema Induratum
DERMATITIS ARTEFACTA
Ulcers in this condition usually occur in crops. This is a very important differential point. The ulcers are also usually superficial but it depends on what has been used to create them. The more caustic compound used, the deeper the ulcers will be.
GSA Dermatitis Artefacta
The photo below is dermatitis artefacta
ORF
Orf is a parapox DNA virus infection usually acquired from the muzzles of orphan lambs or sheep, hence the condition is usually seen in farm workers, vets or shearers. The initial nodule may resemble pyogenic granuloma, in view of its speed of onset. It resolves over a 6-8 week period. Some cases can show subsequent erythema multiforme.
Search eMedicine Image of Orf causing erythema multiforme
eMedicine-Orf
The photo below is orf in a vet
BEHCET'S SYNDROME
The skin lesions in this condition can take a variety of forms, including ulcers, pustules, features of vasculitis, recurrent cellulitis, erythema nodosum, recurrent superficial and deep thrombophlebitis, pustules after venipuncture, follicular papules or pustules, hidradenitis suppurativa or pyoderma gangrenosum.
An interesting fact to remember is that causes of recurrent cellulitis include Behcet's, lymphedema, familial Mediterranean fever and Well's Syndrome.
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eMedicine-Behcet's Disease
GSA Behcet's syndrome Behcet's ulcers on the scrotum
The photo below is of multiple oral ulcers in Behcet's syndrome
eMedicine-Bazin's disease-Erythema induratum
Global Skin Atlas-Erythema Induratum
DERMATITIS ARTEFACTA
Ulcers in this condition usually occur in crops. This is a very important differential point. The ulcers are also usually superficial but it depends on what has been used to create them. The more caustic compound used, the deeper the ulcers will be.
GSA Dermatitis Artefacta
The photo below is dermatitis artefacta
ORF
Orf is a parapox DNA virus infection usually acquired from the muzzles of orphan lambs or sheep, hence the condition is usually seen in farm workers, vets or shearers. The initial nodule may resemble pyogenic granuloma, in view of its speed of onset. It resolves over a 6-8 week period. Some cases can show subsequent erythema multiforme.
Search eMedicine Image of Orf causing erythema multiforme
eMedicine-Orf
The photo below is orf in a vet
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| Note the extensive exudate on the surface |
BEHCET'S SYNDROME
The skin lesions in this condition can take a variety of forms, including ulcers, pustules, features of vasculitis, recurrent cellulitis, erythema nodosum, recurrent superficial and deep thrombophlebitis, pustules after venipuncture, follicular papules or pustules, hidradenitis suppurativa or pyoderma gangrenosum.
An interesting fact to remember is that causes of recurrent cellulitis include Behcet's, lymphedema, familial Mediterranean fever and Well's Syndrome.
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eMedicine-Behcet's Disease
GSA Behcet's syndrome Behcet's ulcers on the scrotum
The photo below is of multiple oral ulcers in Behcet's syndrome
HOW WOULD YOU DIFFERENTIATE HERPANGINA AND HAND, FOOT & MOUTH DISEASE?
Herpangina affects the pharynx and has small ulcers and hand, foot and mouth disease affects the soft palate and has linear vesicles.
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GSA Hand Foot and Mouth Disease
The photo below shows the typical linear vesicles of Hand-footand mouth disease
CLASSIFICATION OF LYMPHADENOPATHY
It is either localised or generalised. If it is tender it means rapid growth or an infection.
The consistency can be rubbery, stony hard or liquefactive.
If the skin over it is inflamed, it usually means there is infective disease in the gland.
If there is matted lymphadenopathy it usually means either TB or lymphogranuloma venereum.
GSA Lymphogranuloma venereum
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The photo below is of cutaneous tuberculosis
DIFFERENTIATE ARTERIAL AND VENOUS ULCERS
Arterial are usually deeper, punched out, often with slough on the base and with little of an inflammatory reaction around about. There is sometimes a symmetrical perilesional vascular halo. Venous ulcers are usually shallow with granulation tissue in the base, sloping edges and often a surrounding inflammatory response.
THALASSEMIA
Ulceration in this condition is usually on the foot and is chronic and superficial. The small blood vessels are blocked by red cells which cannot distort to fit them.
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ATROPHIE BLANCHE
Atrophie blanche is probably best named livedoid vasculitis but it does not show leukocytoclastic vasculitis. There are small painful purpuric eruptions that slowly heal with small stelate white scars and these are what are called atrophie blanche. There may also be telangiectasia, a bit of iron pigmentation and sometimes even livedo. Venous stasis disease is probably the main cause of atrophie blanche. Livedoid vasculitis is a vasculopathy, a chronic recurrent segmental hyalinizing vasculopathy of the small blood vessels. Fibrin IgM and C3 may be found in the vessel walls. Image
Archives-Atrophie Blanche-What is it?
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PubMed -Lipodermatosclerosis
VENOUS ULCER
You do not get a venous ulcer on the sole of the foot. An ulcer there is either arterial or neuropathic.
DERCUM'S DISEASE (Adiposis Dolorosa)
This is usually seen in obese menopausal women who have symmetrical tender, fatty deposits, particularly on the thighs. The presence of these is sometimes associated with weakness and psychiatric disturbances. The lesion is usually referred to as a 'bag of worms' which subsequently ulcerates.
eMedicine-Dercum's disease
The photo below is of venous ulceration
Questions
1. What underlying conditions are commonly seen with pyoderma gangrenosum?
2.Radiotherapy is a recommended treatment for epithelioma cunniculatum?
3.Dermatomyositis is an example of Dystrophic calcinosis. True or False?
4.Is the prognosis in penile scc derived from verrucous carcinoma better or worse than other causes of penile carcinoma?
5.What other conditions other than Behcets has pathergy been described in?
6.Regarding Orf- Infection from fomites ,can it occur ?
7. Erythema Induratum- What test may be used to differentiate erythema induratum from idiopathic nodular vasculitis?
Answers
1. Inflammatory bowel diseases such as Crohns disease and ulcerative colitis. Myeloproliferative disorders such as chronic myeloid leukaemia. Arthritis of various types both seropositive and seronegative. PAPA syndrome (look it up!) Note only 50% of cases have an underlying disorder.
2. No. Radiotherapy is contraindicated for this condition.
3.True-calcification occurs in damaged tissue and serum calcium and phosphate are normal.
4.Better prognosis.
5. Pyoderma gangrenosum,Sweet's syndrome,and bowel associated dermatosis arthritis syndrome.
6.True as the virus is resistant to heat and dryness.Erythema multiforme may also occur secondary to orf.
7.Polymerase chain reaction looking for evidence of TB.
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| Lipodermatosclerosis and atrophie blanche |
