Topics discussed in this Tutorial
Different types of Pustular Psoriasis
Amyloidosis
Juvenile Xanthogranuloma
Letterer Siwe Disease
Epidermolytic hyperkeratosis
Skin lesions in Thyroid disease
Variants of Discoid Lupus
Pigmented Purpuric Dermatoses
Pachyonychia Congenita
Leprosy
What are the different types of pustular psoriasis?
Answer
There are the localised and generalised types. The localised include acral psoriasis or palmoplantar pustulosis. There is the Hallopeau variant. There is the juvenile napkin localised pustular psoriasis.
The generalised type includes the Von Zumbusch’s where there is a generalised sheet of pustules, the exanthematous where there are discrete pustular lesions. The Von Zumbusch’s like type may be due to steroid withdrawal. Images in GSA of pustular psoriasis
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| Stable plaque psoriasis became pustular after intra articular steroid injection |
What is the classification of amyloidosis?
Answer
There is a systemic and several localised variants. The systemic type of amyloidosis tends to localise to the fingers and face whereas the localised types particularly macular amyloid is on the upper back and lichen amyloid is primarily on the lower limbs as a brown papular scaly itchy rash. Images in GSA Note that amyloidosis can involve the larynx causing hoarseness and it is a cause of leonine facies.
Juvenile Xanthogranuloma Image in GSA
These pinkish yellow nodules can occur at an early age. They may be single or multiple but are generally self-limiting. They particularly affect the eyes, the lungs, the liver and spleen. Note an association with neurofibromatosis and watch lymphomatoid papulosis as a differential diagnosis.
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| Periocular bleeding from capillaries in myeloma associated primary systemic amyloidosis. |
This is an acute histiocytosis usually present at birth presenting with seborrhoeic dermatitis papules and purpura. Often the condition occurs in crops. The purpura is particularly in the small of the back, the trunk and the axillae and babies with this condition may have recurrent infections. The Hand-Schuller-Christian type of histiocytosis occurs in two to five year olds. Occasionally in adults. It will present with diabetes insipidus, proptosis and bone lesions. They may have chronic otitis media. Image in GSA
The eosinophilic granuloma variant tends to present with bone lesions and genital or perianal lesions.
What is epidermolytic hyperkeratosis?
Answer
This is mainly a histopathological finding with clumped keratohyalin granules and vacuolisation of the stratum spinosum and granulosum. It is a feature of several of the ichthyoses as well as the Vorner type of palmoplantar keratoderma. You can see it sometimes in epidermal nevi, in sporadic papules such as epidermolytic acanthomas and sometimes as a chance finding in normal skin. If you see it in an epidermal nevus the issue is often raised as to whether this is a form of mosaicism or whether bullous ichthyosiform erythroderma, which is a form of epidermolytic hyperkeratosis, may occur in a subsequent pregnancy. Images in GSA of Epidermolytic hyperkeratosis
Skin Lesions and Hypo and Hyperthyroidism
The skin is basically cold, dry and there are often dermatitic features particularly asteatotic eczema. There may be telangiectasia of the skin with mucin around the eyes causing swelling, pruritus is common, the fingers often have a doughy feeling and the patient may show carotenemia. The facial lines tend to be flattened because of facial oedema and the hair is often dry, coarse and thinned.
The skin lesions in hyperthyroidism include thyroid acropathy with drum like thickening of the nails and nail bed, the skin is often thin, sweaty, hyperaemic, the nails may show onycholysis and there may be pretibial myxedema.
What are the major variants of discoid lupus?
Answer
They may be local or general. Lupus profundus occurs particularly on the lower legs. There may be no overlying features of lupus but just dermal atrophy or an area of fat atrophy. There is the angiolupoid variant, hypertrophic lupus erythematosus, and there is lupus pernio or chilblain lupus. These variants may represent about 6% of the total number of discoid lupus cases. Chilblain lupus can affect the nails with subungual hyperkeratoses and it can look red or there may be a bluish colouring of the nail plate and the nail can in fact crumble.
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| Tumid discoid lupus |
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| Chilblain lupus of the toes |
There are various names attached to this characteristic purpuric eruption on the lower legs and you will often call it a capillaritis because of the very small vessels that are damaged and the low level of that damage. Gravitational purpura is a common cause with associated varicose veins. However the named variants include lichen aureus, which is made up of orange/red macules that are grouped. They are sometimes solitary and there are only a few lesions. Image of lichen aureus
There is Schamberg’s variant, which gives a cayenne pepper type rash on the lower legs. Images in GSA
The Gougerot-Bloom variant gives lichenoid like lesions, which are symmetrical on the lower legs Image in GSA and there is the Majocchi variant that occurs in young adults sometimes with central clearing and an annular appearance .
There is another variant called itchy purpura, which occurs in men on the lower legs with a progressive spread. It is useful to check for cryoglobulins, carbromal sensitivity and check for any abnormal immunoglobulins in the blood. There is also a rare contact purpura to some types of wool giving rise to pigmented purpuric dermatosis. I saw a case once in a foundry worker who wore a special woollen pair of trousers to protect himself from any direct heat damage. A similar rash on the lower legs can also be seen in golfers in the summer who walk the course.
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| Pigmented purpura or capillaritis |
Patients with this condition show large thickened nails, leukoplakia, keratosis pilaris and often a pressure keratoderma on the feet. As an aside if you see grouped milia on the big toe think of dystrophic epidermolysis bullosa. Acral milia after blistering are also seen in PCT and EBA.
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| Thickened nails in pachyonychia congenita |
In lepromatous leprosy you have symmetrical nodules, leg oedema, stuffy nose and the lesions have a diffuse edge. In borderline leprosy you have thickened nerves and in indeterminant leprosy you have macular lesions, pink in white individuals and white in black individuals. In borderline tuberculoid you have a diffuse outer edge but a defined inner edge, some sloping to the outer and lesions can be annular and band like. This is the commonest type of leprosy with anaesthesia, lack of hair and no sweating in the centre of the lesions. In tuberculoid leprosy it is often hyperpigmented with a sharp outer edge sloping to the centre. Note the difference with borderline. Again the lesions are anaesthetic with no hair and no sweating and there are thickened nerves particularly the ulnar and the posterior auricular. It is interesting though that if tuberculoid leprosy is on the face you do not get the lesional anaesthesia.
Images of Lepromatous leprosy in GSA
Images of Tuberculoid leprosy in GSA
Images of Indeterminate Leprosy in GSA
