Generality
Granuloma annulare is a skin disease of an inflammatory nature, which causes the appearance of small raised skin lesions, arranged in a ring or semicircle.
Figure: Generalized annular granuloma.
It is a benign and rather frequent pathology, the cause of which is unknown; however, because it resembles certain autoimmune diseases, it is suspected that it may have a "very similar origin" to the latter.
Apart from the cutaneous signs characterized by the typical circular formations, annular granulomas are often asymptomatic (they do not cause pain and at most there is a slight itch).
For a correct diagnosis, a skin biopsy is required.
As for the treatment, in general, spontaneous resolution of the lesions is expected. In fact, the use of medical treatment is reserved only for the most serious cases or in the presence of aesthetic discomfort on the part of the patient.
What is granuloma annulare?
Granuloma annulare is a skin disease characterized by the appearance, on the skin, of red-pink bumps (also called papules or lesions) and arranged in a ring or semicircle.
What is a granuloma?
In medicine, a granuloma is a neoformation of an inflammatory nature, with a proliferative and nodular nature, consisting of granulation tissue (N.B: the following cells are present in the granulation tissue: monocytes, lymphocytes, plasma cells, histiocytes, macrophages, etc.).
IMMUNE SYSTEM AND AUTOIMMUNE PATHOLOGIES
The immune system is the defensive barrier of an organism against threats coming from the external environment, such as viruses, bacteria, parasites, etc., but also from the inside, such as for example "crazy" (tumor) or malfunctioning cells.
The immune system is made up of an "army" of cells and glycoproteins that are very effective and very aggressive towards those who represent a potential danger.
In some individuals, very often for unknown and unclear reasons, the immune system undergoes an alteration that causes it to attack some perfectly healthy cells of the organism, attacking them. All this can cause damage, sometimes even very serious, to various organs and tissues of the body.
It is this abnormal behavior of the immune system that distinguishes so-called autoimmune diseases.
TYPES OF RING GRANULOMA
Based on the characteristics with which it occurs, granuloma annulare can be distinguished in the following forms (or types):
- Localized annular granuloma
- Generalized annular granuloma
- Granuloma annulare of the mottled type
- Subcutaneous annular granuloma
- Perforating annular granuloma
- Granuloma annulare typical of HIV infections (AIDS)
EPIDEMIOLOGY
Granuloma annulare is thought to be a fairly common condition, however precise data on the true incidence and prevalence are not available.
It was found that the most affected subjects are young and adult people (around 30 years of age) and that the female sex is more interested than the male one.
The most common granuloma annulare is the localized form, which characterizes about ¾ of cases.
The second most common type of granuloma annulare is generalized (10-15% of cases).
The most observed form in children is subcutaneous annular granuloma: the affected subjects are generally between 2 and 5 years old.
Finally, the less common type of granuloma annulare is the perforating type, which can affect both young people and adults alike.
Causes
The precise causes of granuloma annulare remain, at the moment, unknown.
Since many people with granuloma annulare also have diabetes, thyroid disorders, tumors, hyperlipidemia, or some autoimmune disease (particularly systemic lupus erythematosus, Addison's disease, and rheumatoid arthritis), some researchers have speculated that there may be a causal relationship. between these pathological conditions just mentioned and the annular granuloma itself.
However, doubts regarding this hypothesis arise in the presence of those patients who, except for granuloma annulare, are completely healthy.
OTHER THEORIES
According to some minor theories, granuloma annulare would be the consequence of an allergic reaction to gluten, copper or tetanus vaccine; according to others, it would be the body's response to a bone fracture.
Symptoms and Complications
For further information: Granuloma Annulare Symptoms
With the exception of bumps on the skin, granuloma annulare is usually asymptomatic (i.e. the patient complains of no symptoms). In the few cases where it causes ailments, these are limited to an itchy and / or burning sensation.
Each type of granuloma annulare has very particular and distinctive characteristics. Below is a brief description of the main forms and their clinical picture.
LOCALIZED RING GRANULOMA
Localized granuloma annulare manifests itself with the appearance of papules with a diameter of about 1-2 millimeters and with a pink-red color (erythema). These papules tend to be arched or to form a real ring with a diameter between one and 5 centimeters.
The center of the annular formations is generally depressed, so much so that the aspect of the affected areas is very reminiscent of the craters of volcanoes.
Sometimes, the most central portion of the rings may have "hyperpigmentation."
The anatomical areas most affected are the hands, feet, fingers and the extensor surfaces of the legs and arms (NB: the term extensor placed next to a limb refers to the part of the limb where the muscles that allow the limb are located. "extension).
GENERALIZED RING GRANULOMA
Generalized granuloma annulare could be mistaken for the localized type, were it not for the fact that the papules are more numerous and, often, a cause of burning and itching.
The typical annular formations can have a variable diameter between 3 and 6 centimeters; before reaching their final size, it can take several weeks or months.
The most affected anatomical areas are the limbs and the trunk.
SUBCUTANEOUS RING GRANULOMA
Unlike other types of granuloma annulare, subcutaneous granuloma annulare is characterized by lesions located in the innermost layers of the skin.
The affected areas are usually the same color as the rest of the skin and have a stiff texture. More than papules, in fact, we speak of nodules.
In most cases, the nodular formations are solitary, although, in some patients, they may present in small groups.
The areas of the body most affected are the lower parts of the legs, especially the surfaces of the shins.
PERFORATING RING GRANULOMA
Perforating granuloma annulare typically presents with pink-red papules with a diameter ranging from 1 to 4 millimeters.
The papules can be isolated or extremely massed together, forming a sort of ring-shaped plaque. Papules are often the cause of itching and pain.
Furthermore, once they have disappeared, the skin lesions tend to leave a hyperpigmented or hypopigmented scar in the area where they were located.
The anatomical areas most affected are the lower parts of the legs, the extensor surfaces of the arms and the back of the hands.
WHEN TO SEEK YOUR DOCTOR
If papules of the type just described and other particular skin signs do not heal spontaneously within a few weeks, it is always good to contact your doctor for a "thorough investigation of the situation."
COMPLICATIONS
Granuloma annulare does not cause particular complications. The only drawbacks to report against him are:
- The aesthetic discomfort created (for example by the generalized type).
- The slow recovery, which could sometimes take several years.
- When the lesions are itchy, the possibility of the papules becoming infected by dint of scratching.
Diagnosis
To diagnose granuloma annulare, doctors do a physical examination, followed by a "laboratory test on a sample of skin cells (skin biopsy)."
OBJECTIVE EXAMINATION
During the physical examination, the doctor observes the skin signs and assesses their consistency. Then, he asks the patient what symptoms he has (burning, itching, etc.), how long the papules have formed and if he is suffering from other pathologies.
SKIN BIOPSY
Skin biopsy consists of the collection and subsequent analysis, in the laboratory, of a small sample of skin cells taken from one or more lesions.
Pathologies that can be mistaken for an annular granuloma and that the skin biopsy allows to exclude (differential diagnosis):
- Psoriasis
- Sarcoidosis
- Leprosy
- Nummular eczema
- Chronic migrant erythema
- Pityriasis rosea
- Tinea corporis (or ringworm)
- Rheumatoid nodules
In the case of granuloma annulare, these cells have a histological (ie tissue) composition which is completely characteristic and unambiguous; for this reason the biopsy examination represents the most reliable diagnostic test currently available.
Treatment
In most cases, granuloma annulare heals spontaneously, without special treatment.
If you resort to drugs or particular therapies, it is only for aesthetic reasons and / or to try to accelerate healing.
Preparations based on corticosteroids represent the main treatments; following, they could be useful: cryotherapy, laser ablation, some immunosuppressive drugs, etc.
Unfortunately, for many patients, the treatments available are not very effective: the results, in fact, are often not very noticeable.
CORTICOSTEROIDS FOR TOPICAL OR LOCAL USE
Corticosteroids are powerful anti-inflammatory drugs belonging to the steroid family. By topical use, it means that the preparation, in the form of a cream or ointment, is applied directly to the affected area.
Topical corticosteroids are intended to improve the appearance of lesions and speed healing.
In case of prolonged use, they can cause several side effects, including: acne, increased hair growth, telangiectasias and skin thinning.
Topical corticosteroids are particularly suitable for localized annular granulomas.
CORTICOSTEROIDS BY INJECTION
Corticosteroids can also be given by injection. The site of inoculation is, of course, the area where the papules reside.
The reasons that push doctors to resort to this therapeutic method are the presence of burning, itching and large ring formations.
OTHER TREATMENTS
As an alternative to corticosteroids, in some patients they also seem to have discrete effects:
- Immunosuppressive drugs. These drugs lower the patient's immune defenses, also reducing the abnormal inflammatory reaction caused by a malfunctioning immune system. This action is especially useful when other autoimmune diseases are associated with the granuloma annulare.
- Oral corticosteroids. They are mainly used in cases of generalized annular granuloma. If taken in high doses and / or for long periods, they can cause serious side effects, such as osteoporosis, hypertension, weight gain, cataracts, diabetes, etc.
- Cryotherapy with liquid nitrogen. Promotes the removal of lesions on the skin and stimulates the growth of new skin. It is indicated in the case of small annular formations (for example in the presence of localized annular granuloma).
- Laser ablation. Helps improve the appearance of lesions on the skin.
- Psoralen followed by UV exposure (PUVA). This treatment serves to improve the appearance of lesions on the skin. Psoralen is a drug that increases the sensitivity of the skin and is given to the patient before exposure to UV rays.
- Antibiotics. Used in combination with each other, preparations such as minocycline, rifampicin and ofloxacin appear to have some positive effects in accelerating healing. However, in some individuals they are completely ineffective.
Prognosis
In almost half of cases, the localized form (which is also the most common) heals after two years and may reappear some time after resolution.
The generalized type can have an even slower course: for some patients, the disappearance of the annular formations can occur even after 10 years. Furthermore, the response to treatments is not always satisfactory.
Subcutaneous annular granulomas very often resolve spontaneously, but are at high risk of recurrence.
Therefore, the prognosis depends on the type of granuloma annulare and how the patient responds to treatments.
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