note by dr. Claudio Italiano
This disease is generally characterized by well-circumscribed areas of non-scarring alopecia of the scalp without alteration of the skin. Sometimes these areas also appear on the beard, armpits, pubis, arms, legs or the whole body (universal alopecia).
"Exclamation-point hair", with rough tips with a brush tip and hypopigmented stem, are generally found on the border of expanding alopecia areas.
Although this condition is recurrent, hair growth usually begins again after several months. In about 20% of patients, alopecia areata also causes horizontal or vertical depressions of the nails.
The etiology and pathogenesis of this manifestation are not clear. According to the most accredited theory, it would treat an immunopathological component (often due to the attack of IgE antibodies, the allergic specific ones, or more generally the second-class human leukocyte antigens and T lymphocytes, in essence it would produce an abnormal immune reaction able to damage, transiently and locally, the hair follicles, on genetically predisposed subjects.
Other hypothesis concerns the amount of iron present in the human body, even if the data are not sufficient to evaluate how much the lack of iron, and generally the malnutrition, has a role in alopecia areata, which leads to conflicting results in medical research Psychological stress is never the cause but is seen as an element that makes the disease worse, few studies have been done to understand what the exact correlation Alopecia on the contrary can certainly be the cause of psychological stress.
Androgenetic alopecia is linked to the activity of 5-alpha-reductase type II, which transforms testosterone into dihydrotestosterone. Endocrinopathies such as GH deficiency, hypothyroidism, menopause, ovarian polycytosis, virilizing tumors or therapies with androgens (although in truth it must be said that the only androgens that damage the scalp are dihydrotestosterone and androstenedione - testosterone catabolites - on the contrary, testosterone has no harmful effect on the hair) can cause baldness.
The fundamental pathological process consists in the acceleration, under androgenic stimulation, of the mitotic phase of the pilaric cycle (anagen I-V) and in the consequent reduction of the differentiation phase, which is normally very long. Since the latter is necessarily incomplete, the stem that will derive from it will be thinner and shorter (vellus). Subsequently atrophic phenomena of the scalp are superimposed, which becomes thin and shiny.
In this phase the vellus disappear. A second pathological process consists in the loss of the individuality of the papillary cycles (characteristic of normal adult scalp) and therefore of their synchronization. This phenomenon is due to the reduction of the duration of the differentiation phase. A third phenomenon is the increase in the kenogen phase: when the hair shaft comes off at the end of the telogen, the follicle is already occupied by another in advanced anagen.
An interval may
appear between the fall of the hair in telogen and its replacement with the new
one in anagen: during this physiological interval (kenogen), the follicle
remains empty. In the androgenetic baldness only the hair in the frontal region
is lost because in this area the alpha 5-reductase is more active, so there is
concentrated more DHT. Or because it is the most peripheral area of blood
circulation in the scalp, ie where the vessels are already thinner in themselves.
- Arsenic poisoning. More common in chronic intoxication, alopecia is widespread
and mainly affects the scalp. Related signs may include muscle weakness and
hypotrophy, areflexia, partial or total loss of vision, bronzy skin and other
color.
- Arterial insufficiency. In this disorder there is a patchy alopecia, typically on the lower extremities, accompanied by a thin, shiny and atrophic skin and thickened nails. The skin becomes pale when the patient's legs are raised and dark when they are brought back into the sloping position. Associated signs include weak peripheral wrists, cold extremities.
- T-cell skin lymphoma More common in the elderly patient,
this form is associated with mucinous alopecia; in the areas of the body can
appear plaques or papules and erythema to zebra.
-Cellulite dissecating of the scalp. It is caused by skin infection of the scalp,
which then drains; manifests itself as nodular areas
- Mycotic infections (see tigne). Tinea capitis with ring type lesion; the hair
is fragile and easily broken.
Hodgkin's disease. Permanent alopecia may occur if the lymphoma infiltrates the
scalp. This is accompanied by edema, itching and hyperpigmentation: associated
signs vary with the extent and location of lymphadenopathy.
- Hypopituitarism. In adults this pathology can manifest itself in a very varied way depending on the hormonal structure. Gonadotrophin deficiency in women causes a reduction or the absence of pubic and axillary hair is accompanied by infertility, amenorrhea and atrophy of the breasts. A similar deficiency in men reduces hair on the face and all over the body and causes infertility, reduced libido, impotence, poor muscle development and reduced testicular, glans and prostate volume. A growth hormone deficiency at an early age can cause short stature. Thyroid stimulating hormone deficiency produces the signs of hypothyroidism; adrenocorticotropic hormone deficiency produces the signs of adrenocortical insufficiency.
- Hypothyroidism In this pathology the hair on the face, scalp and genitals are thin and become opaque, rough and brittle. More characteristic is the fall of the most lateral part of the eyebrows. Constipation, exhaustion, cold intolerance and weight gain also appear. Other signs are hoarseness, inelastic skin, oedematous face and hands, slowing of mental functions and bradycardia, menorrhagia and myalgias.
- Lichen planus. Sometimes, this skin condition causes a patchy hair fall on the scalp with inflammation of the skin. Flat and purple irregular papules usually develop on the lumbar regions, genitals, arms and legs. Related findings include itching and nail changes ranging from furrow formation to their fall.
- Lupus erythematosus. Hair loss is a frequent early symptom in patients with discoid or systemic lupus. The hair tends to become brittle and can fall into locks; short, broken hair ("Lupoid hair") is frequently present on the forehead. Both types of lupus are characterized by desquamated, red and raised plaques, with occluded follicles, telangiectasia and central atrophy. Facial plates often take on a characteristic butterfly shape. In systemic lupus, however, the rash may vary in severity from malarial erythema to discoid lesions. Unlike the discoid lupus, the systemic lupus inleress multiple systems of the organism. It can cause photosensitivity, weight loss, exhaustion.
- Progressive systemic sclerosis. It is determined alopecia with thickening of the skin of the arms and hands, skin that becomes taut and shiny.Deficit di proteine
- It is associated with alopecia the nutritional deficiency of proteins, for example in the deficiency states, in tuberculosis, in anorexia, in neoplasia, in malabsorption.
-Sarcoidosis. Responsible for scarring alopecia, due to fever, exhaustion, lymphadenopathy; is due Sarcoidosis is a chronic systemic inflammatory disease, discovered in 1860, whose causes remain unknown. It is characterized by microscopic formations, called granulomas, which can be localized in various locations such as the lungs, the bone, the joint joints, the muscles, the vessels, etc .; these formations, in some cases, subvert the structure of the fabric and compromise its function.
-Seborrheic dermatitis. It manifests with sebaceous areas on the skin folds and hair loss, with desquamating and secretive areas of the skin of the face, around the nose fins, etc.
- Hyperthyroidism. ln this disease there is a widespread loss of hair, more
pronounced at the temples. The hair becomes soft and crumbly. The skin becomes
uniformly reddened and thickened, marked by red, pruritic and detected lesions.
Characteristically this pathology causes of the fine tremon and nervousness,
increase in thyroid volume, sweating, heat intolerance, amenorrhea, palpitations,
weight loss despite, increased appetite, diarrhea and probably exophthalmos.
Chemotherapy drugs, such as bleomycin, cyclophosphamide, dactinomycin,
daunorubicin, doxorubicin, fluorouracil and methotrexate, can cause reversible
patchy alopecia, some weeks after their administration. Hair loss is usually
limited to the scalp, but in long-term chemotherapies it can also affect the
armpit, the arms, the legs, the face and the pubis. New hairs, which may differ
in thickness, structure and color from the original ones, can start to grow
after the drug is discontinued or in the interval between subsequent treatments.
Other common drugs can cause a loss of hair spread on the scalp, a few weeks
after administration. These include oral contraceptives, colchicine, I'eparin,
warfarin, excessive dosage of vitamin A, trimetadione, indomethacin,
methysergide, valproic acid, carbamazepine, gentamicin, I 'allopurinol, lithium,
adrenergic beta-blockers and antithyroid drugs. Hair growth usually starts again
when these drugs are stopped.
As with some medications, radiotherapy causes a reversible and temporary fall of
hair a few weeks after exposure, as the x-ray damages the hair follicles in the
therapy site, the radiotherapy of the skull or scalp determines the most obvious
hair loss .
Alopecia can have a devastating impact on the image that the patient has of himself, especially if it is very extensive and occurs suddenly, as happens with chemotherapeutic drugs. It is necessary to explain to the patient that this hair loss is reversible. Sometimes, methods of cooling the scalp, such as a cryogen, a hat filled with ice or a lace applied on the scalp, can be used before, during and after the administration of the drug, to cause a vasoconstriction of the scalp and then reduce the release of the drug to hair follicles and lose hair. However, these methods are contraindicated in cancers with circulating malignant cells, such as lymphoma, and in the metastases of the scalp. A skin biopsy can be performed to determine the cause of alopecia, especially if skin changes are evident. Microscopic examination of fallen hairs may also be helpful for diagnosis.
In patients with partial baldness or aerated alopecla, topical application of
minoxidil is a common antihypertensive drug that causes hair growth for several
months as a side effect. stimulates localized growth of new hair. However, hair
loss can relapse if the drug is stopped.
Advice for the patient
A healthy hair care must be encouraged to avoid further losses. Furthermore,
when appropriate, the use of a parucca, a cap should also be suggested in order
to avoid perfrigeration and cooling of the scalp with deterioration of the skin.
To reduce the risk of skin neoplasms, it should be encouraged to use of sun
blocking creams for patients who are frequently exposed.
Dermatologia
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