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Topics covered in this tutorial
The Differential Diagnosis of Transepithelial Elimination
The Dermatoses of Amputees
Infantile Eczema and Recurrent Infection
Questions will also be asked on the following conditions -
Necrolytic migratory erythema
The differential diagnosis of lichen nitidus
Conditions with keratinous plugs
Sarcoidosis on the face
The differential diagnosis of scarring and non-scarring alopecia
Chloracne
Conditions Causing Transepithelial Elimination
Perforating sarcoid
Pseudoxanthoma elasticum Image in GSA
Elastosis perforans serpiginosa
Perforating folliculitis
Granuloma annulare Image in GSA
Lichen nitidus
Papular mucinosis
Rheumatoid nodule
Necrobiosis lipoidica Image in GSA
Porokeratosis
Chondrodermatitis nodularis helicis
Calcinosis cutis Image in GSA
Nevocellular nevi
Malignant melanoma
Infective Causes-Bacteria, Protozoa, Fungi.
The Differential Diagnosis of Trans epithelial Elimination
Perforating diseases involve those where material is eliminated from the dermis through the epidermis to the outside surface of the skin. The conditions listed below all have abnormal material laid down in the dermis ranging from granulomatous material to degenerate elastic tissue and collagen and calcium. Each of the conditions usually has a plug of some sort that can be picked out leaving a crater which will extend all the way down into the dermis. The site at which the condition is found is usually a good clue as to the underlying diagnosis, for example perforating folliculitis is usually seen on the extensor surfaces of the upper arms, buttocks and thighs, Kyrle's Disease is usually on the lower legs, reactive perforated collagenosis is usually seen in sites of frequent trauma such as the backs of the hands, forearms, elbows and knees.
Perforating disease of human dialysis which seems to be a wrap around term to include examples of perforating folliculitis, Kyrle's Disease and reactive perforating collagenosis seen in patients with chronic renal failure and often associated diabetes. It is understood to develop in between 4 and 10% of dialysis patients. Again the lesions are primarily on the legs. Early lesions may be pustular with late lesions resembling prurigo nodularis.
Perforating sarcoidosis and perforating granuloma annulare is often seen on the dorsum of the hands, papular mucinosis particularly on the lower legs, rheumatoid nodules are mainly around joints, necrobiosis lipoidica is usually on the anterior shin.
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| Elastolytic granuloma O'Brien's Granuloma |
Infantile Eczema and Recurrent Infection
Think of ataxia telangiectasia
Chronic granulomatous disease
Wiskott Aldrich syndrome
Jobs syndrome
Letterer Siwe disease Image
Therefore look at the eyes for telangiectasia. This may not come on until the ages of two to three.
Archives on atopic dermatitis and Job's Syndrome
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| Ataxia telangiectasia Note Sclera |
Dermatoses of Amputees
On the lower limb the lesions are usually -
Verrucous
Verrucous hyperplasia
Follicular plugging
PubMed-Skin problems of Amputees
mechanically induced blisters, follicular keratoses, epidermoid cysts, stump edema syndrome, acroangiodermatitis (pseudo-kaposi sarcoma) and verrucous hyperplasia.
This is an excellent practical article on the topic
Chloracne
This condition presents with small black follicular plugs and papules mainly on the areas over the cheeks and behind the ears and somewhat surprisingly on the scrotum. It is usually found in people involved in manufacturing chlorinated compounds. Exposure to benzine compounds may also cause this condition and also dioxin compounds. The condition is usually thought of when acne seems to be occurring in very unusual areas. In chloracne the nose is very resistant. The duration of the lesions can vary from six months to 30 years. The initial lesion is a comedo but the lesions progress to form yellow cysts. Cold abscesses can also occur and the degree of inflammation is much less than in cystic acne. Scarring is not uncommon. PCT may also be seen in patients suffering from chloracne. Granuloma annulare lesions on the dorsum of the hands may also occur and hyperpigmentation of a generalised nature can be seen in late cases.
The Seveso Study Also Wikipedia on Chloracne
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| Chloracne |
Sarcoidosis of the Face
Four types can be seen in the face. The commonest is the annular type but you may also see angiolupoid, lupus pernio and papular. Sarcoid on the face can scar.
Other unusual forms of sarcoidosis that may be seen are -
Scar sarcoid where scars from various causes may be infiltrated with sarcoidal tissue, but this can also include tattoos.
Ichthyosiform resembling ichthyosis vulgaris.
Alopecia which may be either due to plaques extending into the scalp causing hair loss or lesions that look like small areas of alopecia areata.
Morpheaform sarcoid - in this latter type sarcoidosis is accompanied by marked scarring giving rise to morphea like lesions. Usually these are plaque like but occasionally can be linear.
Mucosal sarcoid involving the mouth usually involves the hard palate.
Subcutaneous sarcoidosis with deep-seated nodules is usually found on the trunk and extremities and only rarely on the face.
Lupus pernio involves peripheral areas of the face particularly the ears and the nose. Many of these cases are associated with granulomas and bone cysts in the fingers and also with chronic ocular lesions.
Ulcerative sarcoidosis is a very rare variant where plaques can ulcerate or ulcerations may occur de novo and really can only be diagnosed by biopsy.
Hypopigmented sarcoid can be a presenting form of the condition but lesions are usually macular. Sometimes on touch a dermal component can be felt.
PubMed -Sarcoidosis GSA Sarcoidosis
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| Annular sarcoid face |
The Differential Diagnosis of Scarring and Non-scarring Alopecia
Scarring alopecia implies permanent destruction of hair follicles. The diagnosis can either be made from the history or the appearance of the lesions or sometimes from concomitant findings. The history will point to those due to congenital factors such as aplasia cutis or alopecia triangularis or those due to various forms of trauma or infections such as Zoster or kerion or even due to tick bites.
The actual physical appearance of the alopecia can lead to the diagnosis in cases due to necrobiosis lipoidica, discoid lupus, scleroderma, metastatic tumour and temporal arteritis.
The diagnosis can be made from concomitant findings in conditions such as incontinentia pigmenti, dystrophic epidermolysis bullosa, pemphigus vulgaris and bullous pemphigoid, porokeratosis of Mibelli.
Question 1 What are the other concomitant findings of incontinentia pigmenti?
The Differential Diagnosis of Non-Scarring Alopecia
These includes androgenic alopecia, Alopecia areata , trichotillomania, fungal infections, telogen effluvium, anagen effluvium, lose anagen syndrome and secondary syphilis.
Question 2 What is the hair collar sign on scalp cysts and what might it indicate?
Answer 2 It is a band of rapid hair growth surrounding a cyst like structure in the scalp with often loss of hair over the cyst. It points to a diagnosis heterotopic brain tissue and an encephalocele or a cutaneous meningioma. Ultrasounds and x-rays should be done to see if there is any connection of the underlying brain itself. Remember that the main thing with any congenital cystic mass in the scalp is to rule out an encephalocele. Do not stick a needle in it before doing the ultrasound and the x-rays.
Lichen planopilaris GSA Images
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| Lichen Planopilaris |
The Differential Diagnosis of Lichen Nitidus GSA Images
The lesions of Lichen nitidus are usually discreet, shiny, flat topped uniform papule about the size of a pinhead but may be found in plaques or the linear forms because of the Koebner reaction. The lesions are typically found on the lower anterior abdominal wall and on the genitals. The differential diagnosis includes flat warts, micropapular lichen planus, but in the latter there are usually larger papules or plaques with violaceous lesions and they are itchy. The lesions of lichen nitidus are usually not itchy.
Occasionally the lesions of lichen nitidus can form hyperkeratotic plaques on the palms and soles. Lichen striatus can resemble linear lichen nitidus, but the papules are usually bigger and scarring and damage to the nails can occur if the nail matrix is involved.
Question Does nail involvement occur with lichen nitidus?
Answer Yes it does with pitting, beading longitudinal ridging and sometimes nail fold inflammation.
Necrolytic Migratory Erythema
This condition is also known as the glucagonoma syndrome generally associated with an endocrine tumour of the pancreas. These are known as APUD cell tumours of the pancreas and they produce various hormones including glucagon.
The eruption is a spreading circinate scaly eruption with a pustular edge around the mouth or perianal areas and sometimes coming out of the flexures. The borders can be gyrate or circinate and hyperpigmentation can occur. There is little response to topical steroids or antifungal preparations. There is often a painful glazed tongue with angular cheilitis. Note that a skin biopsy will show hyperkeratosis and irregular epidermal acanthosis with pallor and necrotic changes confined to the upper epidermis.
Question Does glucagon itself cause the features of this rash?
Answer No, the glucagon appears to cause amino acids, zinc and essential fatty acid deficiencies because supplementation of these substances leads to improvement of the rash.
PubMed-Glucagonoma Syndrome Recurrent annular erythematous scaly patches
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| Necrolytic migratory erythema |
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