Other benign tumours
A wide variety of tumours may develop from the hair follicle and sebaceous, exocrine sweat , and apocrine glands. The more common include syringomas slowly growing, small, multiple nodules on the face of eccrine gland origin. Naevus sebaceous is warty, well defined, varying in size from a small nodule to one several centimetres in diameter. Lesions occur in the scalp of children, may be present at birth, and gradually increase in size. They may proliferate or develop into a basal cell carcinoma...
Scabiespoints to note
There may be very few burrows, though the patient has widespread itching The distribution of the infestation is characteristically the fingers, wrists, nipples, abdomen, genitalia, buttocks, and ankles Close personal contact is required for infestation to occur, for example, within a family, through infants in playgroups, and through regular nursing of elderly patients Itching may persist even after all mites have been eliminated itching papules on the scrotum and penis are particularly...
Infections
Any type of opportunistic infection is more likely in patients with AIDS and will generally be more severe. An itching, inflammatory folliculitis occurs in many cases. The cause is unknown, but it is possible that Demodex spp. play a part. Superficial fungal infections are often much more extensive and invade more deeply into the dermis than usual. There may also be granuloma formation. Deep fungal infections that are not normally seen in healthy individuals occur in AIDS patients as...
Psoriasis
The familiar pink or red lesions with a scaling surface and well defined edge are easily recognised. These changes can be related to the histological appearance Increased epidermal proliferation nuclei found throughout the epidermis Increased epidermal proliferation nuclei found throughout the epidermis The increased thickness of the epidermis, presence of nuclei above the basal layer, and thick keratin are related to increased epidermal turnover. Because the epidermis is dividing it does not...
The typical patient
Psoriasis usually occurs in early adult life, but the onset can be at any time from infancy to old age, when the appearance is often atypical. The following factors in the history may help in making a diagnosis There may be a family history if one parent has psoriasis 16 of the children will have it, if both parents, the figure is 50 . The onset can occur after any type of stress, including infection, trauma, or childbirth. The lesions may first appear at sites of minor trauma Koebner's...
Mycetoma Madura foot
This is a chronic infection of the dermis and subcutaneous fat caused by various species of fungus eumycetoma or bacteria actinomycetoma . Both types look the same with a swollen foot and multiple discharging sinuses, but it is important to differentiate between them because the treatment is different. Examination of the discharging grains colour will give a clue as to the cause . Culture of the grains to identify the causative fungus or bacteria. If no grains can be found a skin biopsy will...
Tar preparations
These are mainly used for treating psoriasis as described in chapter 3. Tar has an anti-inflammatory effect and seems to suppress the epidermal turnover in lesions of psoriasis. The various tar pastes are generally too messy to use at home and are most suitable for dermatology treatment centres. Standard tar paste contains a strong solution of coal tar 7-5 in 25 g of zinc oxide, 25 g of starch, and 50 g of white soft paraffin. There are numerous proprietary preparations that are less messy and...
Localised alopecia
Alopecia areata is a common form of hair loss. It is seen in 2 of patients attending the average dermatology clinic in the United Kingdom. There may be small patches of hair loss or the whole scalp may be affected. Resolution occurs in a few months or the condition may persist for years. There may be slight inflammation of the skin in the affected areas in keeping with the possibility of an underlying immune reaction against the hair follicles. There is also an association with autoimmue...
Contact dermatitis
The skin normally performs its function as a barrier very effectively. If this is overcome by substances penetrating the epidermis an inflammatory response may occur leading to epidermal damage. These changes may be due to either a an allergic response to a specific substance acting as a sensitiser or b a simple irritant effect. An understanding of the difference between these reactions is helpful in the clinical assessment of contact dermatitis. Common sources of allergic contact dermatitis...
Solar urticaria
This is a much less common condition and may be induced by longer wavelength ultraviolet A and visible radiation as well as ultraviolet B. It is characterised by rapidly developing irritation and in the exposed skin is followed by urticarial wheals. It can occur as part of a photoallergic reaction, in which case avoidance of the relevant allergen will prevent the condition. Treatment is with antihistamines and sunscreens. In some cases phototherapy with ultraviolet B, narrow waveband or...
Rosacea
Rosacea is a persistent eruption occurring on the forehead and cheeks. It is more common in women than men. There is erythema with prominent blood vessels. Pustules, papules, and oedema occur. Rhinophyma, with thickened erythematous skin of the nose and enlarged follicles, is a variant. Conjunctivitis and blepharitis may be associated. It is usually made worse by sunlight. Rosacea should be distinguished from Acne, in which there are blackheads, a wider distribution, and improvement with...
Larva migrans
The patient in the illustration had been on holiday at a tropical coastal town and regularly visited a beach frequented by dogs. Two weeks after returning to Britain he started itching on the buttocks and subsequently noticed a linear, raised area a condition known as larva migrans, due to the larvae of the hookworm of dogs and cats, Ancylostoma caninum. The ova are shed in the faeces and in a warm moist environment hatch into larvae that invade dead end hosts. They do not develop any further,...
Variants
Variants of the usual pattern can cause problems in diagnosis. Cystic basal cell carcinomas occur, and those that show differentiation towards hair follicles or sweat glands may Basal cell carcinoma later stage of figure above Basal cell carcinoma later stage of figure above have a less typical appearance. Pigmented lesions can resemble melanoma. The superficial spreading type may be confused with a patch of eczema. This usually occurs on the trunk, does not itch, and shows a gradual but...
Development duration and distribution
Several diseases may present with blisters or pustules. There is no common condition that can be used as a reference point with which less usual lesions can be compared in the same way as rashes can be compared with psoriasis. A different approach is needed for the assessment of blistering or pustular lesions, based on the history and appearance, and is summarised as the three Ds development, duration, and distribution. Was there any preceding systemic illness as in chickenpox, hand, foot, and...
Treatment Gbu
Localised lesions of herpes simplex have been treated with a variety of medications from zinc sulphate to iodoxuridine. Topical acyclovir a drug that inhibits herpes virus DNA polymerase is effective but only shortens the duration of illness by a day or so. It is useful in primary infection but should be used as soon as the patient is aware of symptoms. Severe, recurrent, herpes simplex, or herpes zoster can be treated with oral or intravenous aciclovir as early in the course of the illness as...
Seborrhoeic dermatitis
Seborrhoeic dermatitis has nothing to do with sebum or any other kind of greasiness. There are two distinct types, adult and infantile. The adult type is more common in men and in those with a tendency to scaling and dandruff in the scalp. There are several commonly affected areas Seborrhoeic dermatitis affects the central part of the face, scalp, ears, and eyebrows. There may be an associated blepharitis, giving some red eyes and also otitis externa. The lesions over the sternum sometimes...
Types of eczema
The many causes of eczema are not consistently related to the distribution and clinical appearance. In general there are either external factors acting on the skin producing inflammatory changes or it is an endogenous condition. It is important to remember there can be more than one cause for example, in atopic eczema or varicose eczema on the ankle an allergic reaction may develop to the treatments used. Atopic eczema affects mainly the flexor surfaces of the elbows and knees as well as the...
Topical steroids
Topical steroids provide effective anti-inflammatory treatment but have the disadvantage of causing atrophy due to decreased fibrin formation and telangiectasis. They are readily absorbed by thin skin around the eyes and in flexures. On the face the halogenated steroids produce considerable telangiectasia, so nothing stronger than hydrocortisone should be used except in lupus erythematosus . They can cause hirsutism and folliculitis or acne. Infection of the skin may be concealed tinea...
Local treatment
Local treatments entail the use of ointments and pastes, usually containing tar in various forms. It is much easier to apply them in hospital than at home if patients can make the time for hospital visits. Inpatient treatment can be more intensive and closely regulated it also has the advantage of taking the patient completely away from the stresses of the everyday environment. In some units a five day ward enables patients to return home at weekends, which is particularly important for parents...
Spider bites
In Europe spider bites rarely cause problems, but sometimes noxious species arrive in consignments of tropical fruit. The patient shown had been bitten by a spider the day before leaving Nigeria and developed a painful necrotic lesion. Bites from the European tarantula are painful but otherwise harmless. In tropical and subtropical countries venomous spiders inject neurotoxins that can be fatal. The black widow Latrodectus mactans , fiddleback Loxosceles veclusa , and Atrax species of Australia...
Early stages
In the early stages 50 of patients have antibiotics to HIV and the p24 antigen can be detected. The proportion of CD4 lymphocytes decreases, and this is associated with the development of secondary changes in the skin. There is also an increase in HIV antibodies so a test for this should be repeated six to eight weeks after the initial illness. Counselling should take place before testing is carried out.
Pityriasis rosea
The word pityriasis is from the Greek for bran, and the fine bran-like scales on the surface are a characteristic feature. The numerous pale pink oval or round patches can be confused with psoriasis or discoid eczema. The history helps because this condition develops as an acute eruption and the patient can often point to a simple initial lesion the herald patch. There is commonly slight itching. Pityriasis rosea occurs mainly in the second and third decade, often during the winter months....
Sedating antihistamines
There are many available and which is used is largely a matter of personal preference. The sedating effect, which is enhanced by alcohol, means that they are best taken at night. They also potentiate CNS depressants and anticholinergic drugs. They tend to have anticholinergic effects, causing dry mouth, blurred vision, tachycardia, and urinary retention. Those commonly used are Chlorphenamine Piriton Stafford-Miller 4 mg daily Cyproheptadine Periactin MSD 4mg up to four times daily Hydroxyzine...
Scarring alopecia
The absence of hair follicles is an important physical sign as it indicates 1 The presence of an inflammatory process that requires further investigation. 2 That there is unlikely to be any substantial recovery of hair growth. The presence of inflammation does not necessarily produce marked erythema in lichen planus and lupus erythematosus, the inflammatory changes are often chronic. Systemic lupus erythematosus produces areas of inflammation that extend, leaving residual scarring. In discoid...
Erythema infectiosum fifth disease
Age. Erythema infectiosum affects children aged two to 10 years, mainly girls. Incubation lasts five to 20 days. Prodromal symptoms. There are usually none, but there may be a slight fever with initial rash. Initial rash. The initial rash is a hot, erythematous eruption on the cheeks hence the slapped cheek syndrome. Over two to four days a maculopapular eruption develops on the arms, legs, and trunk. Development and resolution. The rash extends to affect hands, feet, and mucous membranes,...
Incisional biopsy and punch biopsy
It is essential to have a working clinical diagnosis, but wherever there is doubt the pathologists can provide much more precise information regarding the nature and extent of the lesion. For example, a patch of Bowen's disease intraepidermal carcinoma may resemble sclerosing superficial basal cell carcinoma and a biopsy will usually distinguish them. Similarly, what seems to be a dysplastic pigmented naevus clinically may, on the one hand, prove to be benign or, on the other hand, turn out to...
Hand foot and mouth disease
Age. Hand, foot, and mouth disease Coxsackie virus A affects both children and adults. Incubation period is unknown. Prodromal symptoms. Fever, headache, and malaise may accompany the rash. Initial rash. Initially there may be intense erythema surrounding yellow-grey vesicles 1-1-5 mm in diameter. These are mainly distributed on the palms and soles and in the mouth. Sometimes a more generalised eruption may develop. Development and resolution. Over three to five days the rash fades. Diagnosis....
Subcutaneous myiasis
Invasion of the skin by the larvae of the tumbu mango fly Cordylobia anthropophaga in central and southern Africa causes this condition. The fly lays her eggs on clothes layed out to dry on the ground. The eggs hatch out two days later on contact with the warm skin when the clothes are put on. The larvae burrow into the skin causing a red painful or itchy papule or nodule, predominantly on the trunk, buttocks, and thighs. Dermatobia hominis tropical bot fly, in Mexico, central, and south...
Seborrhoeic warts
Seborrhoeic warts come in various shapes, sizes, and colours. When deeply pigmented, inflamed, or growing they may appear to have the features of a malignant lesion, but the following features are characteristic Warty, papillary surface often with keratin plugs. Raised above surrounding skin to give a stuck on appearance. Individual lesions vary considerably in size, but are usually 0-5-3-0 cm in diameter. Protuberant and pedunculated lesions occur. Solitary lesions are commonly seen on the...
Tungiasis
Invasion of the skin by sand fleas Tungapenetrans causes tungiasis in tropical areas of Africa, America, and India. It is most common on the feet, especially under the toes and toenails. The condition looks a bit like plantar warts, but if you watch for a while you will see the eggs being squirted out. Carefully winkle the fleas out with a pin most patients know how to do this themselves . If the fleas are very extensive, soak the feet in kerosene or treat with a single dose of ivermectin 200...
Pityriasis lichenoides
Pityriasis lichenoides is a less common condition occurring in acute and chronic forms. The acute form presents with widespread pink papules which itch and form crusts, sometimes with vesicle formation suggestive of chickenpox. There may be ulceration. The lesions may develop in crops and resolve over a matter of weeks. The chronic form presents as reddish brown papules often with a mica-like scale that reveals a smooth, red surface underneath, unlike the bleeding points of psoriasis. In lichen...
What is acne
Acne lesions develop from the sebaceous glands associated with hair follicles on the face, external auditory meatus, back, chest, and anogenital area. Sebaceous glands are also found on the eyelids and mucosa, prepuce and cervix, where they are not associated with hair follicles. The sebaceous gland contains holocrine cells that secrete triglycerides, fatty acids, wax esters, and sterols as sebum. The main changes in acne are thickening of the keratin lining of the sebaceous duct, to produce...
Treatment
When new epidermis can grow across an ulcer it will, and the aim is to produce an environment in which this can take place. To this end several measures can be taken 1 Oedema may be reduced by means of a diuretics b keeping the legs elevated when sitting c avoiding standing as far as possible d raising the heels slightly from time to time helps venous return by the calf muscle pump e applying compression bandages to create a pressure gradient towards the thigh. 2 Exudate and slough should be...
Arterial ulcers
Ulcers on the leg also occur as a result of a atherosclerosis with poor peripheral circulation, particularly in older patients b vasculitis affecting the larger subcutaneous arteries and c aterial obstruction in macroglobulinaemia, cryoglobulinaemia, polycythaemia, and collagen disease, particularly rheumatoid arthritis. Applying ichthopaste bandages as a protective layer Applying ichthopaste bandages as a protective layer Take measures to eliminate oedema and reduce weight make sure the...
Pityriasis versicolor
Pityriasis versicolor is a skin eruption that usually develops after sun exposure with white macules on the tanned skin but pale brown patches on the covered areas, hence the name versicolor, or variable colour. The lesions are a flat b only partially depigmented areas of vitiligo are totally white and c do not show inflammation or vesicles. The causative organism is a yeast, Pityrosporum orbiculare, that takes advantage of some unknown change in the epidermis and develops a proliferative,...
Molluscum contagiosum
The commonest skin infection due to a pox virus is molluscum contagiosum, a skin infection seen particularly in children. Despite its name it is not very contagious, but can occur in families. In adults florid molluscum contagiosum may be an indication of underlying immunodeficiency, as in AIDS patients. The white, umbilicated papules of molluscum contagiosum are characteristic. Large solitary lesions may cause confusion as can secondarily infected, excoriated lesions. These lesions often itch,...