Tutorial 14

Topics discussed in this Tutorial

Pruritus

Anetodermas

Molluscum, Miliaria, Staph Scalded Skin

Skin manifestations of Diabetes

Yellow nail syndrome

Lichen Planus, Lichen sclerosus

Periungual Fibromas

Nail bed tumours and Other nail disorders

What is your mnemonic for pruritus? Answer I use the mnemonic SCRATCHED. S for senile, C for cirrhosis, R for renal, A for autoimmune, T for tumours, C for crazy, H for haematological, E for endocrine and D for drugs. Senile pruritus is probably the most common. We see it in the winter months especially in people in Nursing Homes and the elderly when the skin dries out. They may get the characteristic crazy paving on the lower legs with splitting of the epidermis.  Image in GSA Cirrhosis and renal failure will certainly give pruritus. Primary biliary cirrhosis is probably the most common liver pathology giving pruritus. Renal failure patients all get itch and some itch persists even after dialysis. Cause of this is not known. The autoimmune diseases causing itch are Hashimoto’s thyroiditis and of course primary biliary cirrhosis. The tumours are particularly lymphomas and Hodgkin’s disease. Crazy patients are just crazy. Watch this though! Make sure they dont have scabies or lymphoma. The haematological diseases are again the lymphomas, possibly iron deficiency anaemia. Endocrine diseases are mainly hypothyroidism and drugs can be virtually any. Certainly any that cause liver or renal damage but a lot of drugs will give subacute urticaria. Some drugs are primary mast cell releasers eg aspirin or codeine and other opiates. Pruritus can be associated with schistosomiasis or you may get urticaria, an urticarial dermatitis rash particularly on the trunk and exposed areas of people who have been swimming in exposed environments. Then they will develop paragenital granulomas and fistulae. In onchocerciasis there is pruritus and dermatitis with erosive areas on the buttocks and lumps near bony eminences. Trichinosis will give food poisoning, muscle pains, splinter haemorrhage, a transient macular papular rash and periorbital oedema. It is the latter that is a particularly characteristic feature of this condition which is usually acquired from pigs. The periorbital oedema can also occur with filariasis. If you have eosinophilia, think about all these diseases. The Anetodermas The anetodermas have the names of Jadasson and Pellagrini attached to them. The Jadasson lesions are solitary. In the Pellagrini variant they become confluent. In the Schweninger Buzzi variant there is acute sudden onset mainly on the trunk and the upper arms, symmetrical and there are large numbers of anetoderma. Most anetodermas will give some wrinkling of the epidermis. Anetodermas can be secondary to lupus, syphillis and acrodermatitis chronica atrophicans. A follicular anetoderma occurs because of an elastase producing staph epidermidis. So if you get anetoderma look for other diseases elsewhere. Anetoderma nodules or outpouchings Molluscum Contagiosum This is a problem disorder. It can have an incubation period from two weeks to two months. Most lesions last less than three months and involute though other new ones take their place. It can be inflamed from trauma or can spontaneously inflame. You can have associated dermatitis and conjunctivitis. Generally you should prick them open and then use 20% Podophyllum in Tinc Benz Co to deal with them. You can also freeze them. Topical cantharidin is available overseas to treat mollusca in adults and children. They may be acquired sexually in adults.  Mollusca images in GSA Miliaria There are various types of miliaria depending on the level of blockage of the eccrine glands. Note that infection and scratching may supervene on a classic miliaria in a child and give associated pustules and infective features. Miliaria profunda is also seen in elderly immobile hospital patients with fevers where you find it mainly on the back. The image below is miliaria crystalina What are often the early features of the staph scalded skin syndrome? Answer Conjunctivitis or some other source of infection, tender red skin and a positive Nikolsky sign. The latter is when pressure is applied to the border of an intact blister the blister extends.It is pathognomonic for pemphigus, toxic epidermal necrolysis, and Staph scalded skin. Question What are the skin manifestations of diabetes? Answer Generally itch, infections, diabetic bullae and dermopathy but there are a variety of associated diseases including necrobiosis lipoidica, granuloma annulare and eruptive xanthomas, the latter being particularly seen in acute undiagnosed diabetics with highly raised triglycerides. Image in GSA   Diabetic dermopathy in GSA There are complications of the disease such as neuropathic ulcers and gangrene. There are complications of treatments such as insulin atrophy or hypertrophy. Other metabolic diseases associated with diabetes such as Cushing’s and acromegaly and there are congenital diseases such as the Lawrence-Seip syndrome.  Acanthosis nigricans is a feature of insulin resistance and hyperinsulinaemia in early diabetes in some individuals.  There are also the more recently recognised disorders such as perforating diseases associated with diabetes that look like prurigo papules on the legs. The image below is of necrobiosis lipoidica

What are the features of the yellow nail syndrome? Answer First of all it is usually associated with chronic lymphedema of the legs or with underlying pulmonary disease particularly bronchiectasis. The clinical features are that the nails are yellow. If they do not grow there is an increased curvature laterally and there are slightly darker edges and hyponychium. View other images of Yellow Nails Lichen Planus Lichen planus of the nails affects essentially the matrix or the nail bed. If it affects the matrix you get onychorrhexis where there is thinning and shortening of the nail and perhaps a pterygium formation. On the nail bed you may get localised onycholysis with subungual hyperpigmentation and onychoatrophy. When dermatitis affects the nail it usually only involves the matrix under the posterior nail fold, therefore you get pitting, transverse ridging and some furrows. Lichen Striatus Lichen Striatus may give involvement of a nail which can become ridged or split but always check the rest of the limb looking for the other features of lichen striatus because there may be some skip lesions. Mind you a linear skin lesion with nail involvement is usually an ILVEN rather than lichen striatus. Psoriasis, if it affects the matrix, gives pits when the abnormal keratin is washed away. You also get the oil drop sign, splinter haemorrhages and subungual hyperkeratosis. Tinea always attacks under the hyponychium and also superficially. You get the characteristic white spots of trichophyton mentagrophytes. Very rarely would you get proximal subungual tinea. Images in GSA Pityriasis rubra pilaris gives subungual hyperkeratosis with longitudinal ridging and erythema and the Sezary’s syndrome gives the same features as pityriasis rubra pilaris. Darier’s disease gives longitudinal alternating white and red bands with nicks at the nail edges. Image in GSA The image below is Lichen striatus Periungual Fibromas These may be subungual or periungual. They are associated with tuberous sclerosis   as a late feature on their own. Alopecia areata can give a yellowish colour change with lustreless nails and lines of pits. Atopic dermatitis gives ragged edges to the nails and buffed surfaces. Question What tumours can cause the nail to separate from the nail bed? Answer Warts, osteoma, giant cell tumour, keratoacanthoma of the nail bed, rarely a melanoma or a pyogenic granuloma. Tumor type Benign / malignant Site of origin (nail unit) How it can cause nail separation (onycholysis) Typical associated features Subungual exostosis Benign Distal phalanx under nail bed Bony outgrowth elevates and destroys part of nail bed, lifting the nail plate Common in great toe, painful firm nodule, often in younger patients Glomus tumor Benign Subungual soft tissue (often nail bed) Distorts nail bed and plate, leading to deformity and possible onycholysis Severe point tenderness, cold sensitivity, episodic pain Digital myxoid (mucous) cyst Benign Near distal interphalangeal joint / proximal nail matrix Mass presses on matrix/plate causing ridging and occasional partial separation Translucent or skin‑coloured cyst, may leak jelly‑like fluid Onychomatricoma Benign Nail matrix Thickened, overcurved nail with distal splitting and lifting of nail plate Yellowish thick nail, “woodworm”‑like holes at free edge, slow growth Onychopapilloma Benign Distal nail matrix / nail bed Localized thickening causes distal fissuring and partial separation Longitudinal band (often red or white), distal splitting, subungual keratosis Subungual melanoma Malignant Nail matrix or nail bed Tumor destroys matrix/bed, causing splitting and progressive separation Pigmented band or patch, nail dystrophy, possible extension to surrounding skin Nail unit squamous cell carcinoma (incl. Bowen disease) Malignant Nail bed, matrix, or periungual skin Infiltrates and erodes nail bed, leading to onycholysis and nail loss Warty or erosive lesion, bleeding, pain, chronic “paronychia‑like” changes Other nail‑specific carcinomas (e.g., onycholemmal carcinoma, onychocytic carcinoma) Malignant Usually nail bed Thickening or erosion of nail bed detaches overlying plate Slow‑growing mass, localized dystrophy, often mistaken for benign lesions                                                                         Koilonychia Question What types of koilonychia do you know? Answer It can be congenital or acquired due to iron deficiency or syndromal as in dyskeratosis congenita and in some of the ectodermal dysplasias. Other Nail Observations Beau’s lines must occur on all the nails because they represent an insult sufficient to interfere with the normal growth of the nail. They are horizontal lines. Hand Foot and Mouth disease is a common cause. Jogger’s nail dystrophy is different from habit nail dystrophy. Habit nail dystrophy tends to have a fir tree like pattern because of irritation and picking at the posterior nail matrix and the lunula. Jogger’s nails get surrounding bruising just from chronic trauma. Image in GSA Remember the nail patella syndrome  Image in GSA          and watch myxoid cysts causing pressure on the nail matrix and a longitudinal depression in a nail. Note with the nails that trichophyton rubrum is anthropophilic and therefore there is not much inflammation. Trichophyton mentagrophytes gives a white surface to the nail. Lateral onycholysis is more typical of psoriasis. Central onycholysis with some haemorrhage is usually due to trauma and watch secondary bacterial infection when you have tinea of the nails. You can sometimes miss it. The image below is of Beau's Lines