Topics covered in this Tutorial
Polymorphous light eruption
Phototoxicity due to Drugs
Nail changes
Pachydermoperiostosis
Bullae in neonates
Perianal fistulae
Ulcers in Rheumatoid arthritis
Ecthyma gangrenosum
Unilateral flushing
Types of Porokeratoses
Morphology of the lesions can be anything you want but generally it is erythema, urticaria, papules, eczema, plaque like, almost like lupus and prurigo like. It is rare to get full-blown blisters. Generally the areas affected are those that are less often exposed to the sun. Note often the first web space and around the elbows especially the lateral surface. Also you tend to find it on the dorsum of the feet and over the thighs. Images of PMLE in GSA
Phototoxicity is usually due to drugs. All areas reached by the sun are affected and there is usually a very sharp clothing cut off. If there is an external photo allergen there are usually patchy areas where the chemical has touched the skin and it has reacted with light. There may be a mixture of cutaneous features depending on the depth of the UV light through the skin, its intensity and any local repair factors. There may just be erythema or bullae due to phototoxicity if there is superficial damage. Images in GSA
The differential diagnosis of polymorphous light eruption includes actinic prurigo, discoid or subacute lupus, lymphocytoma and acute contact dermatitis.
Polymorphous light eruption usually you see in people under 30, it is more chronic and it is usually in females. Actinic prurigo is usually seen under the age of 10, it improves, it is very itchy and it is again in females. In photosensitive atopic dermatitis you will usually find evidence of atopy elsewhere. In hydroa vacciniforme you have bigger scars than actinic prurigo and they are not itchy and appear in males more than females. In hydroa vacciniforme there can be blisters that are umbilicated and have a red base. They all scar. It is worse in summer and it is quite episodic. You can get associated photo onycholysis. The eyes may be involved but it tends to cease by late adolescence. Compare this with porphyria cutanea tarda where you will get skin fragility and milia but there is no red base to the blisters and it is seen an older age group.
The image below is of juvenile spring Eruption
What nail changes may you get with Tetracyclines?
Photo onycholysis, which can occur with both Minocycline and Doxycycline. Minocycline can also give a longitudinal brown band as well. Tetracycline Hydrochloride, which is no longer available here in Australia, can cause onycholysis. It can cause a bluish residue in the nail bed and nail. It can cause splinter haemorrhages and pain and it can cause yellow lunulae with fluorescence.
The image below is of onycholysis.
This condition is usually seen in the scalp as a primary type. It is an autosomal dominant condition that comes on at puberty where you can get the face thickening as well as folds in the scalp or you can get thick hands and feet. They can get clubbing. There is some degree of mental retardation. Images in GSA
A secondary type can occur with an underlying lung carcinoma, it is painful and the skin changes are mild. The other condition to remember is cutis verticis gyrata. This can occur first of all at puberty with hypertrophy and folding of the scalp only, it is an autosomal dominant and a lot of people have a low IQ. There is a marked increase in seborrhoea. Secondly it can be part of pachydermo periostosis. Thirdly it can be part of acromegaly and fourthly secondary to local inflammatory disorders such as infection and cellulitis. Images in GSA
eMedicine on Pachydermoperiostosis
The image below is of pachydermo periostosis.
Bullae in Neonates
You can get blistering dactylitis which is streptococcal and involves the tips of the fingers. You can have bullous impetigo and a long list starting with epidermolysis bullosa. Note you will get eosinophils in transient neonatal pustular melanosis and also in the Ofugi’s syndrome and also often in insect bite reactions. Images
Dermnet on other causes of dactylitis
The image below is of Blistering Dactylitis
Vascular disease
If you have an ulcer with no sweating and no surrounding hair then it is probably an arterial ulcer. With microvascular disease you will get distal gangrene on several toes and this is commonly seen in diabetes.
This is generally seen as part of a pseudomonas infection. It is usually seen in a very toxic immunosuppressed individual. You get erythema first and then bullae and then an eschar formation.
The image below is of Ecthyma gangrenosum in an infant.
What are the causes of perianal fistulae?
Answer
The first condition to think about is underlying Crohn’s disease. However it can also occur with TB, granuloma inguinale, secondary to diverticulitis or malignancy, secondary to ischiorectal abscesses, syphilis, amoebiasis and botryomycosis.
The image below is of the perianal fissures and fistulae of Crohn's disease.
Ulcers in Rheumatoid Arthritis
They can be due to stasis ulcers, vasculitic ulcers, due to prostheses, weight bearing problems and pyoderma gangrenosum.
If you have an ulcer induced by an X-Ray there will be a lack of vascularity and they also have some evidence of scarring and telangiectasia.
This causes ulcers, which are painless. There are no local glands and the ulcers are sharply defined.
What are the causes of the punctate keratodermas?
They include Darier’s disease, lichen planus, porokeratosis, Richner Hanhart syndrome, arsenic and familial.
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| Punctate keratoderma |
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| Punctate keratoderma |
Tyrosinemia Type 2
It causes punctate, palmar plantar keratodermas particularly in infancy, which may improve. They get severe keratitis and mental retardation. The palmar and plantar lesions are painful and tender to touch. It is helped by a diet low in tyrosine and phenylalanine.
The image below is of granuloma inguinale
What are the types of granuloma annulare?
First of all you can have localised and generalised. You can have subcutaneous, perforating, micropapular, annular, linear , elastolytic and there is a giant form. It is also seen in Mauriac’s syndrome where you have juvenile diabetes, stunted growth and hepatomegaly.
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| Perforating granuloma annulare |
What types of sarcoidosis do you know?
Clinically you could have papular, micropapular, anular, nodular, scar, lupus pernio, erythema nodosum, angiolupoid and a miscellaneous group including ulcerative, psoriasiform, palmar plantar and inguinal. Nearly all types of sarcoid appear on the face.
What are the features of rosacea?
First of all you can have papules, telangiectasia, pustules, erythema and oedema but you have sparing generally of the nasolabial areas. Sebaceous hyperplasia is seen in some cases giving rinophyma. Involvement of the naso labial areas with scaling is usually due to seborrhoeic dermatitis.
What causes of unilateral flushing do you know?
There is Sphenopalatine syndrome where you get pain, oedema, rhinitis, excess tearing and erythema. There is the Auriculo Temporal syndrome. You get no pain but you will get erythema and hyperhidrosis. There is the Ciliary syndrome where you have pain, erythema, headaches, no rhinitis but you get cluster headaches. You have the Melkersson-Rosenthal syndrome (oral facial granulomatosis) but there is no redness or pain and there is oedema. Compare this with the Sphenopalatine syndrome. In the hypertensive Diencephalic syndrome you get excess sweating and blotching of the skin of the face and the neck with salivation and tachycardia and a sustained hypertension. You have to exclude pheochromocytoma and also consider the Riley Day syndrome in adults. Note you have pain in the skin in Sphenopalatine syndrome but no pain with Melkersson-Rosenthal syndrome.
The image below is of severe rosacea.
Types of Porokeratosis
First of all there is DSAP, this can be a familial type in women in their 40s, autosomal dominant, especially on the legs or they can be solar induced where there are a lot fewer of them. Generally DSAP begins as a 1mm to 3mm papule around the follicle containing a keratotic plug. The central area becomes atrophic, hypopigmented or occasionally hyperpigmented.
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| DSAP Disseminated Superficial Actinic Porokeratoses |
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| DSAP Disseminated Superficial Actinic Porokeratoses |
Porokeratosis of Mibelli varies in size. Oral lesions can occur. It is often in covered areas. You can get a systematised zosteriform or linear variant in childhood. SCC may develope in lesions in the fourth decade. You can have punctate and palmar planta porokeratoses. Porokeratoses Mantoux are not hereditary. They occur in young adults particularly on the fingers where you get a parakeratotic horny mass, overlying dilated capillaries and small amount of haemorrhage. They shed over several weeks leaving small pits that then disappear.
The image below is of a large porokeratosis of Mibelli.
