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.
Search eMedicine Search Perplexity AI
Topics covered in this tutorial
1. The DD of papules.
2. Eyelid papules.
3. Acral papules.
4. Oral papules
5. Yellow papules
Questions will also be asked on the following disorders-
Lymphomatoid papulosis.
Sarcoidosis.
Pseudoxanthoma elasticum
Lipoid proteinosis
Lichen amyloid
The Diagnosis of Papular Diseases
These are probably best diagnosed by dividing them into papules on certain sites, papules with certain colours and papules with certain patterns.
The sites are namely the eyelids, the mouth, acral and follicular. The colours are yellow, blue black and skin coloured and the patterns are linear, circinate, single, multiple, symmetrical, those associated with bullae, scaling and non scaling.
Oral Papules The differential diagnosis includes oral florid papillomatosis, Darier's Disease, tuberous sclerosis, Cowden's Syndrome, acanthosis nigricans, multicentric reticulo histiocytosis, lipoid proteinosis, Goltz Syndrome, Heck's Disease.
Eyelid Papules Naevi, warts particularly mollusca, syringomas, sarcoidosis, acnitis, amyloidosis, See this case of lipoid proteinosis.
Acral Papules Warts, acrokeratosis verruciformis, epidermodysplasia verruciformis, Gottron's papules, multicentric reticulo histiocytosis, sarcoidosis, lichen planus, granuloma annulare.
Asymptomatic labial papules in a teenager
The photo below is of lymphomatoid papulosis
Syndromes with Acanthosis Nigricans
These include Prader Wili, Sjogren Larsen, Rudd's, Down's, Lawrence Seip, Leprechaunism, Wilson's Disease, Polyendocrine Syndrome. In the benign form of acanthosis nigricans most patients show features of obesity and insulin resistance. The malignant form of AN is far less common, and, in one study, only 2 of 12,000 patients with cancer had signs of AN.
GlobalSkinAtlas Acanthosis nigricans eMedicine-Acanthosis nigricans eMedicine-Lawrence-Seip Syndrome
Symmetrical black plaques on the toes
Syndromes with Poikiloderma
The list includes Rothmund Thompson Syndrome, Bloom's Syndrome, Cockaynes, Dyskeratosis Congenita, Erythropoietic Proto Porphyria and Werner's Syndrome.
The age of onset of the poikiloderma is a good way of separating out these conditions.
Oral Papules The differential diagnosis includes oral florid papillomatosis, Darier's Disease, tuberous sclerosis, Cowden's Syndrome, acanthosis nigricans, multicentric reticulo histiocytosis, lipoid proteinosis, Goltz Syndrome, Heck's Disease.
Eyelid Papules Naevi, warts particularly mollusca, syringomas, sarcoidosis, acnitis, amyloidosis, See this case of lipoid proteinosis.
Acral Papules Warts, acrokeratosis verruciformis, epidermodysplasia verruciformis, Gottron's papules, multicentric reticulo histiocytosis, sarcoidosis, lichen planus, granuloma annulare.
Asymptomatic labial papules in a teenager
The photo below is of lymphomatoid papulosis
Syndromes with Acanthosis Nigricans
These include Prader Wili, Sjogren Larsen, Rudd's, Down's, Lawrence Seip, Leprechaunism, Wilson's Disease, Polyendocrine Syndrome. In the benign form of acanthosis nigricans most patients show features of obesity and insulin resistance. The malignant form of AN is far less common, and, in one study, only 2 of 12,000 patients with cancer had signs of AN.
GlobalSkinAtlas Acanthosis nigricans eMedicine-Acanthosis nigricans eMedicine-Lawrence-Seip Syndrome
Symmetrical black plaques on the toes
Syndromes with Poikiloderma
The list includes Rothmund Thompson Syndrome, Bloom's Syndrome, Cockaynes, Dyskeratosis Congenita, Erythropoietic Proto Porphyria and Werner's Syndrome.
The age of onset of the poikiloderma is a good way of separating out these conditions.
| Syndrome | Typical onset of poikiloderma | Key associated features in children | Malignancy risk |
|---|---|---|---|
| Rothmund–Thomson syndrome (poikiloderma congenitale, RECQL4) | Facial rash in infancy, evolving to poikiloderma by 3–5 yearsncbi.nlm.nih+1 | Short stature, sparse hair/eyebrows, photosensitivity, juvenile cataracts, skeletal anomalies (radial/thumb defects, bone dysplasia), dental anomalies, GI symptoms, hypogonadism, possible developmental delaylink.springer+2 | High risk of osteosarcoma in late childhood/adolescence and non‑melanoma skin cancers; other internal malignancies reportedonlinelibrary.wiley+1 |
| Kindler syndrome (KIND1/FERMT1) | Poikiloderma appears in early childhood after infancy blisteringpmc.ncbi.nlm.nih+2 | Acral trauma‑ and photosensitive blistering in infancy, photosensitivity, progressive poikiloderma on photoexposed sites, skin atrophy, mucosal fragility, strictures (oral, esophageal, urogenital), periodontitispmc.ncbi.nlm.nih+1 | Increased risk of cutaneous squamous cell carcinoma in adulthood reportedjamanetwork |
| Poikiloderma with neutropenia (C16orf57/USB1) | Early childhood poikiloderma, often first years of lifeonlinelibrary.wiley+1 | Chronic neutropenia with recurrent sinopulmonary and skin infections, nail dystrophy, palmoplantar hyperkeratosis, short stature, facial dysmorphism; bone marrow failure may evolvemedlineplus | Elevated risk of myelodysplastic syndrome and acute myeloid leukemiaonlinelibrary.wiley+1 |
| Dyskeratosis congenita (telomere biology disorders) | Childhood or adolescent poikiloderma, often reticulated pigmentation on neck/upper chestonlinelibrary.wiley+1 | Classic triad: abnormal reticulated pigmentation, nail dystrophy, oral leukoplakia; plus bone marrow failure, pulmonary and hepatic fibrosis, developmental delay in some subtypessciencedirect | High risk of bone marrow failure, myeloid malignancy, solid cancersonlinelibrary.wiley+1 |
| Hereditary sclerosing poikiloderma (Weary type and related) | Early childhood onsetsciencedirect+1 | Generalized or acral poikiloderma with progressive dermal fibrosis/sclerosis, flexion contractures, possible tendon/ligament involvement; usually little systemic malignancy risk reportedsciencedirect | Malignancy risk less well defined; not a classic cancer‑predisposition syndromeonlinelibrary.wiley+1 |
| Hereditary fibrosing poikiloderma (e.g. POIKTMP/FAM111B) | Infancy/early childhood poikilodermaonlinelibrary.wiley+1 | Progressive poikiloderma, tendon contractures, myopathy, lipodystrophy; systemic fibrosis may involve lungs, pancreas, and other organsonlinelibrary.wiley | Data limited; some reports of internal organ dysfunction rather than frank cancer predispositiononlinelibrary.wiley |
Chronic plaques in a patient with ataxia telangiectasia
The photo below illustrates acanthosis nigricans on the neck Click here to view this case
Cowden's Syndrome
In this condition there are often pearly papules on the palms and soles with also papules at the side of the lips and tricholemmonas on the face. This syndrome is associated with internal malignancies, particularly of the breast and thyroid. Note-If you see a patient with what you think are warts on the face have a close look at their gums and see if there are verrucous lesions there. Then look more carefully at the skin for lipomas, fibromas lymphangiomas and angiomas. The warty lesions on the skin will be trichilemmomas.
Other Central Facial Papules
Multiple trichilemmomas Image
Multiple trichilemmomas
Adenoma sebaceum (multiple angiofibromas)
Darier disease
Syringomas (usually located under eyes as opposed to perinasally)
Fibrofolliculomas (in Birt-Hogg-Dube syndrome) Image
eMedicine-Cowden's Syndrome
Multiple facial papules in an adult
Trichoepithelioma
Trichoepithelioma is a skin coloured papule found on the nasal labial folds and eyelids. It is worse at puberty. This should be compared with tuberous sclerosis which is better at puberty. Trichoepitheliomas are often found in association with cylindromas. It is due to the presence of an autosomal dominant gene on chromosome 9 which can show dimorphism and variable penetration. Linear and dermatomal forms of trichoepithelioma may sometimes be seen as well as a variant with a large hemifacial plaque.
eMedicine-Trichoepithelioma Image
The photo below is a solitary desmoplastic trichoepithelioma
Lichen Amyloid
Lichen Amyloid is a papular disorder seen particularly on the lower limbs with the pathology being in the lower dermis. This can be compared with lichen myxedematosus where the lesions are usually seen in the upper limb and the pathology is in the upper dermis. The lesions of lichen amyloid are brown, slightly scaly, discrete papules but often they will join up to form infiltrated plaques, particularly over the shins. They are usually very itchy. The papules of lichen myxedematosus are often waxy, dome shaped or flat topped papules. They also can coalesce into plaques and linear forms are known.
GSA Lichen Amyloidosis eMedicine-Lichen Amyloid
Skin induration with multiple flesh coloured papules
Kyrle's Disease
These are hyperkeratotic papules up to 1 cm in diameter with confluence sometimes producing polycyclic plaques. It spares the palms and soles. It is found especially on the legs in the 30 to 60 year age group.
eMedicine-Kyrle's Disease Image
Question: Are mucosal lesions present in lichen myxedematosus?
Answer: Mucosal lesions are absent in lichen myxedematosus
The photo below is lichen amyloidosis
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| Itchy hyperkeratotic papules particularly on the lower legs |
Lipoid Proteinosis
Note that this condition is often seen at birth and is associated with hoarseness in the newborn baby. This is due to an infiltrate in the vocal chords. The lesions typically affect the oral mucosae. The tongue is often like wood. Eyelid papules are commonly seen in this condition.
Globalskinatlas- Lipoid Proteinosis eMedicine-Lipoid Proteinosis
Buschke-Ollendorff Syndrome
Buschke-Ollendorff Syndrome is an autosomal dominant disorder with widespread dermal papules and plaques, mainly asymmetrically on the trunk and limbs. Osteopoikilosis is seen in the long bones. Connective tissue naevi are also seen in tuberous sclerosis and because at least 50% of cases of this condition are new mutation, every patient with a connective tissue naevus should be checked for evidence of tuberous sclerosis.
eMedicine-Buschke-Ollendorf Syndrome Image
Widespread pea sized papules and gooseflesh plaques in a 44 years old woman
Question 1: What skull x-ray features are pathognomonic for lipoid proteinosis?
Question 2: Early stage lipoid proteinosis may produce bullae and pustules which heal with acne like scars. What other condition may this simulate?
Question 3: What two features are common to both tuberous sclerosis and lipoid proteinosis?
Answer 1: Sickle-shaped calcifications found dorsal and lateral to the sella turcica in skull x-rays are pathognomonic.
Answer 2: Erythropoietic Protoporphyria.
Answer 3: Both have cerebral calcification and papules on the eyelids.
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| Angiofibromas of tuberous sclerosus |
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| Periungual fibroma |
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| Cutaneous fibroma plaque |
Sarcoidosis
The skin involvement of sarcoid is either specific showing granulomas on histology or non-specific, mainly reactive such as erythema nodosum. Skin lesions appear before systemic disease in 20% of cases, there is a simultaneous appearance in 50% and in 30% the skin lesions may occur up to 10 years after the systemic disease, often when oral steroids are withdrawn in pulmonary sarcoidosis. Papular sarcoid is particularly common on the face.
Global Skin atlas - Sarcoidosis eMedicine-Sarcoidosis
Off-Centre Fold Recurrent Pruritic papules in a 74 years old man An Unusual cause of hair loss Erythroderma in a patient with arthritis,uveitis and dyspnoea Hypopigmentation of the extremities
The photo below is annular sarcoidosis
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| Small sarcoidal papules looking like granulomatous rosacea |
Question 2: What systemic features may be seen with lupus pernio?
Question 3: Do you get sarcoidosis in the mouth?
Answer 1: Annular - the face and forehead.
Papular - the face
Nodular - the trunk
Angiolupoid - the eyelids
Chilblain-like - the ears, the nose, the cheeks
Scar like - needless to say in scars
Ulcerative - on the legs
Hypopigmented - on the trunk
Erythrodermic - all over the body
Ichthyosiform - particularly the trunk
Alopecia - obviously the scalp
Answer 2: 75% of cases have respiratory tract involvement, 40% have granulomas in bones with punched out cysts, generally on the fingers. Eye lesions occur in about 40% of cases.
Answer 3: Yes, there may be pinhead sized papules, particularly on the hard palate, tongue and buccal mucosa but they may coalesce to form a plaque.
Yellow Papules
Yellow Papules
A mnemonic for yellow papules is SEXI Grannies. S stands for sebaceous, E for elastotic disorders, X for xanthomas, I for infiltrates, particularly lipoid proteinosis, lichen amyloid, EPP and colloid milium. Grannies stands for granulomas.
GSA - Pseudoxanthoma elasticum eMedicine-Pseudoxanthoma elasticum
Multiple light yellow papules
Pseudoxanthoma Elasticum
The photo below is of colloid milium.The pale area has been lasered with a CO2 laser.
Answer: They are breaks in the elastic membrane of Bruch at the back of the eye. Eight five percent of PXE patients will show these. These lesions appear earlier than the skin changes and may be the only sign of the disease for years. Angoid streaks are not diagnostic for PXE and may be seen in several other skin diseases and Paget's Disease of bone and Sickle Cell Disease. The papules in PXE are yellowish to cream coloured, the skin is crepe like, lax with redundant folds, the so-called plucked chicken skin. It is often seen on the neck or the inside of the upper arms.
Cowden's Syndrome
Trichilemmomas are a specific cutaneous marker for Cowden's Syndrome. These lesions particularly occur on the head and neck. Patients with Cowden's Syndrome have a marked increase in carcinoma of the breast, thyroid and colon. Other benign features include acral keratotic papules and oral mucosal papules.
Multiple facial papules in an adult
The photo below is of perifollicular fibromas
Answer: In fibro folliculoma there is proliferation of the follicular epithelium as strands extending into a well circumscribed mantle of connective tissue. In perifollicular fibroma the hair follicle is generally unaltered but the follicles are surrounded by a concentric arrangement of collagen fibres. Both lesions are seen in the autosomal dominant disorder known as the Birt-Hogg-Dube Syndrome. Individuals with this syndrome and their relatives should have abdominal tomography for renal cancers, ultrasound screening for renal tumours
Lymphomatoid Papulosis
These lesions usually occur in crops anywhere on the body. There may be very few lesions. The lesions are similar to those of pityriasis lichenoides et varioliformis acuta except that they have a greater tendency to necrosis. Some of the lesions have a tendency to heal spontaneously. The lesions often heal with scarring.
GSA - Lymphomatoid Papulosis eMedicine-Lymphomatoid Papulosis
Red nodules on the arm of a patient with breast cancer
The photo below is lymphomatoid papulosis .This subsequently evolved into a CD 30 positive T cell lymphoma
Answer: Mycosis fungoides in 40% a CD 30-positive T cell lymphoma in 30% and Hodgkin's Disease in 25%. Note that the presence of clonal rearrangement in lymphomatoid papulosis lesions is not predictive of the behaviour of that lesion or the case in general.
What are the skin signs of Dermatomyositis?
Periocular violaceous erythema with ragged cuticles and periungual capillary dilatation. There are often violaceous papules on the legs like lichen planus and erythema, particularly on the dorsal surfaces of the knees and elbows. Photo sensitivity is often seen. Calcification occurs particularly in children.
A patient with dermatomyositis and linear streaks on the back Dermatomyositis-Practical aspects
Finger Pulp Ulcers and Scars
These can be due to Raynaud's Disease, perniosis, scleroderma, systemic lupus, cryoglobulinemia, rheumatoid arthritis and sub acute bacterial endocarditis.
| Cause category | Key mechanisms / examples | Notes / typical context |
|---|---|---|
| Poor blood flow (digital ischemia) | Raynaud’s phenomenon, prolonged vessel narrowing, ischemia of fingertip skin | Fingers may change colour with cold or stress; can progress to “digital” ulcers. |
| Systemic sclerosis / scleroderma | Scarring and narrowing of small arteries, recurrent tip ulcers | Often very painful ulcers at tips or under nails; common in scleroderma. |
| Trauma and pressure | Repetitive minor trauma (tapping, tools, instruments, sports, biting/picking) | Dry or thin skin splits; in poor circulation, small injuries become chronic ulcers. |
| Infection | Paronychia, felon, infected hangnails, other local finger infections | Can ulcerate if untreated; recurrent infections may leave pitted or thickened scars. |
| Connective tissue / vasculitic disease | Lupus, rheumatoid arthritis, vasculitis affecting small vessels | Vessel inflammation and occlusion → fingertip ulcers, sometimes in multiple digits. |
| Metabolic / vascular risk factors | Diabetes, smoking, high blood pressure, high cholesterol | Microvascular disease and poor healing increase ulcer risk and delay recovery. |
| Occupational / chemical exposure | Irritants (detergents, solvents), wet work, vibration tools | Skin cracking and splitting, Raynaud-like changes in some workers using vibrating tools. |
| Neurological / behavioural factors | Neuropathy (numbness), habitual picking or self-injury | Injuries go unnoticed or are self-inflicted, become chronic wounds and scars. |
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| Ragged cuticles of dermatomyositis |
