Dangerous mites

In most case the mites are accidental and temporary invaders and they are not able to permanently colonize or reproduce on the human skin.While in some case they live in the skin of the host.

Scabies or sarcoptic mange	It play a significant role in the incidence of dermatologic diseases in man, it is due by mites Sarcoptes scabiei that colonize the corneus layer of the skin.Clinical features: warty crusts form on the hands and feet and the palms and soles may be irregularly thickened and fissured. Erythema and scaling occur on the neck, scalp and trunk, and may generalize. Itching is often severe. The clinical features in infants are different: in addition to the more extensive distribution of burrows mentioned above, vesicular and vesiculopustular lesions on the hands and feet are not uncommon, crusted nodules on the trunk and limbs may be present.Diagnosis: include the extraction and identification of scabies mites (bodies and eggs) by examination of scrapings.Allergic sensitivity to the mite or its products appears to play an important role in detemining the development of lesions other than burrows, and in producing pruritus. Evidence suggests that both immediate and delayed-type hypersensitivity are involved, skin tests with mite extracts show positive immediate-type reactions.Treatment: sulphur 10% in yellow soft paraffin a concentration of 2.5% may be used for scabies in infants. Hot bath and vigorous scrubbing of the sites of burrows was considered not necessary. Benzyl benzoate dermal cream were effective, the whole body, except the head and neck should be treated for three consecutive days (once a day). Treatment must be repeted after seven days. Permethrin dermal cream is also effective. Disinfestation is not necessary, clothing and bedding can be wash by ordinary laundering.
Dermatitis	Dermatitis is a pruriginous irritation of the skin.It has been suggested that the dermatitis caused by mites, results from irritation by mite products, either faecal or secretory. The pathomechanics of the response do not appear to have been studied in detail.The eruption provoked by these mites is sometimes called "copra itch" or "grocer's itch", and is composed of minute, intensely pruritic papules or papulovesicles on exposed parts of the body, principally on the head and neck, and forearms.
Urticaria	In some subject the application of house dust mites can produce a papule within an hour after application. A link between house dust mites and urticaria can not be completely rejected.
Atopic Dermatitis or Atopic Eczema	Mites are an important cause of allergic diseases in children and their role in AD has been debated for many years. Mites belonging to Acaridae and Pyroglyphidae families are involved .It is known that the patch test with allergens can induce skin lesions that have most of the morphological and histological characteristics of AD. It has also been demonstrated that, in a majority of patients with AD, eczematous reactions similar to the spontaneous lesions could be induced by skin patch testing with mite antigens. It has also been hypothesized how transcutaneous sensitization might occur. Kanerva et al. showed a decrease of Langerhans OKT6+ cells in superficial epidermis and an increase of these in derma where an inflammatory reaction of the hair follicles was also present. The allergens might enter the epidermis by the hair follicles and get in contact with Langerhans cells. Immunohisthological studies of the induced cutaneous lesions showed an eczematous reaction with epidermal spongiosis, microvesiculation and dermal cell infiltrates mainly consisting in T lymphocytes ( ratio of T4:T8, 2-6:1).Moreover, the number of basophil and mast cells did not exceed 10 - 15 % (12). Cutaneous lesions could be caused by delayed hypersensitivity and cell-mediated reaction.Therefore, the most appropriate material for the mite patch test may be the whole culture containing all of the mite allergens which should be applied to intact skin, even though it has been hipothesized that the body allergens play a more important role in AD than in allergic respiratory diseases. In fact, there is evidence that the serum of AD patients has relatively higher titles of specific IgE antibodies against mite-body ( Der p II ) than against mite faecal allergen Der p I. Storage mites, particularly Glycyphagus domesticus, may play an important role as the cause of AD in children.The role of specific IgE in AD is unclear, and the term atopic is sometimes criticised.A possible role of IgE is suggested by the existence of IgE bound to Langerhans cells by low-affinity Fc-IgE receptors in skin lesions of AD patients with elevated serum IgE levels.Langerhans cells may bind and present allergens to T lymphocytes, thereby inducing an inflammatory response.The mite patch test is not pathognomonic for atopic dermatitis, though Glycyphagus domesticus and Tyrophagus putrescentiae proved to be more positive in children with AD. This method could be used to evaluate hypersensitivity to mites along with traditional methods for the diagnosis of allergic diseases.The degree of positivity to Pyroglyphidae patch test was significantly linked to the skin test.Therapy: avoidance of dust mites is almost impossible to achieve (vacuum-cleaning, plastic coverings over mattresses).The desensitization has discussed.

Species	Damage
Pyemotes ventricosus	Bronchial asthma in grain workers Ancona, 1923
Pyemotes tritici	They induce very numerous urticated papules surmounted by vesicles in grain handlers localized on the forearms, neck, around the waist and in the groins.
Sarcoptes scabiei	This species causes scabies in man and mange in a wide range of domestic and wild mammals, throughout the world. There is one species Sarcoptes scabiei , with nine different forms, which infests a very wide range of mammalians hosts (Fain,1968).In man only one species is able to produce mange, whilst many varietas of this species may cause it dermatitis.
Psoroptes spp	It cause psoroptic mange in
Demodex folliculorum	The pathogenicity of hair follicle mite in man is still disputed.D. folliculorum has been implicated in the pathogenesis of "pityriasis folliculorum", a condition described as occurring predominantly in middle-aged or older women who rarely wash their faces, but use large quantities of make-up and deansing creams. This dermatosis is characterized by diffuse facial erythema and follicular scales. The role of the mites in rosacea have produced conflicting results. It has been suggested that a local delayed hypersensitivity response to Demodex antigens might be partly responsible for the inflammatory component of rosacea. Skin scrapings contain unusually large numbers of Demodex. The beneficial effects of metronidazole might be mediated through an action against Demodex.Rosacea-like eruptions in which large numbers of mites could be demonstrated have been described. In some patients mites is present in eyelash follicles, and has been implicated in the pathogenesis of blepharitis. Itchy papular eruption can be osserved in HIV patients, microscopy or histology of scrapings, confirms the presence of numerous mites. There is a rapid response to topical treatment with insecticides.
Demodex brevis	In human sebaceous glands.
Glycyphagus domesticus	Grocer's itch after repeated contact
Lepidoglyphus destructor	Hay itch
Tyrophagus putrescentiae	Copra itch
T. longior	Ham itch
Acarus siro	Baker's itch
Rhizoglyphus robini	Occur on flower bulbs and have caused dermatitis in persons handling stored bulbs.
Spider mites	They cause cutaneous irritation or urtication in man, these mites are phytophagous and occur on every type of crop and ornamental plant.
Cheyletiella parasitivorax	These mites are non-burrowing obligatory parasites of certain mammals, predominantly dogs,cats and rabbits. Most affected animals are asymptomatic, but some may suffer from pruritus. The most obvious sign of infestation is excessive dandruff especially on the back, which is often known as "walking dandruff".They can attack man inducing erythematous macules at the sites of the bites, and these gradually develop into intensely itchy papules and tiny vesicles.Lesions are localized around the feet and ankles, the groins and genitalia, the axillae, the wrists, and antecubital fossae.Skin test with an extract of Cheyletiella mites produced both immediate and delayed hypersensitivity responses.Once an animal has been treated effectively there will be no further lesions on its owner.
Cheyletiella yasguri	It is a parasite of dogs capable of causing a dermatitis in man for contact with the skin of infected dogs and trigger symptoms of true allergy.
Carpoglyphus lactis	It is found on all kinds of dried fruit, and may cause dermatitis.
Dermanyssus gallinae	It can bite man and provoke dermatitis.
Ornithonyssus spp.	It can bite man and provoke dermatitis and allergies.
Neotrombicula autumnalis	It can bite man and provoke dermatitis.

Dangerous mites

i.2 - Skin disorders