What Is Galli-Galli Disease?
Galli-Galli Disease (GGD) is a very rare and unidentified genodermatosis with an autosomal dominant pattern of inheritance and varying penetrance. Still, some instances with no family history have been reported. Galli-Galli genodermatosis is a benign but extremely itchy and undesirable condition. It is thought to be inherited. It is thought to be caused by mutations in the KRT5 gene, similar to DDD. Clinically, it is marked by reticulated hyperpigmentation that mostly affects the flexures, and, like DDD, it is accompanied by itchy, erythematous, scaly papules. Histopathologic analysis shows suprabasal focal acantholysis and digitiform elongation of the rete ridges, which are characteristics of DDD.
What Are the Signs of Galli-Galli Disease?
The first presentation is marked by erythematous brownish papules and macules that occasionally combine to form reticulated plaques, along with the progressive, reticular, symmetrical, and partially lentiginous pigmentation in the flexures (the inguinal folds, neck, breast, and axillary). The second presentation is characterized by erythematous papules and macules broadly dispersed throughout the neck, back, trunk, limbs, and belly without involving the flexural folds. It has only been detected in a minority of patients and is therefore considered atypical.
What Are the Causes of Galli-Galli Disease?
Several etiological factors might cause the inflammatory response. Sweat was the main aggravating factor, followed by UV exposure and high temperatures. A significant association between genotype and phenotype has been found in GGD. Mutations in the KRT5 gene have been shown to cause cutaneous involvement, particularly in the flexural areas, leading to the typical clinical presentation.
What Is the Diagnosis of Galli-Galli Disease?
There is no particular lab test or staining for GGD. Therefore, clinical-pathological correlation and, when practical, genetic analysis are used to make diagnoses. A high index of suspicion is necessary because several disorders, such as DDD, Grover disease (GD), and Darier's disease (DD), can have clinical and histological correlations with GGD and frequently overlap in features. A biopsy is necessary to differentiate between two entities. The characteristics of both disorders are similar, including melanosis, dermal fibrosis, epidermal thinning of the epithelium, hyperkeratosis, perivascular lymphocytic infiltration, and epidermal ridge hyperplasia. At the same time, DDD typically lacks the suprabasal acantholysis seen in GGD. It has been emphasized that many skin samples from various locations or serial sections are required to identify acantholysis.
The following characteristics are indicative of GGD: multiple acantholysis foci in the granular and upper spinous layers; digitated hyperplasia of the epidermal ridges, filiform, basal hyperpigmentation of the rete ridge tips, and suprapapillary epidermis narrowing with a widened granular cell layer. Dyskeratotic keratinocytes can also be observed. These results can differ based on the disease's stage and are not always present.
During the inflammatory phase, histiocytes, lymphocytes, and a few eosinophils penetrate the papillary dermis. Epidermal spongiosis foci adjacent to acantholytic foci may develop into scale-crusted and papulovesicular lesions. During the noninflammatory phase, dermatosis is asymptomatic and clinically and histologically similar to DDD.
Histopathologically, there is minimal visible skin inflammation and little to no acantholysis. Only melanin deposits in the papillary dermis, and digitate hyperplasia of epidermal ridges are observed at this stage. Other findings are possible: acanthosis, parakeratosis, dyskeratosis, hypergranulosis, follicular comedo-like cysts, and hyperkeratosis.
What Is the Treatment of Galli-Galli Disease?
There are currently no standard procedures for managing Galli-Galli disease (GGD), and there is little evidence to support the efficacy of any particular course of treatment. However, certain precautions might be given to patients, such as avoiding wearing tight clothing that can cause irritation and using sunscreen to prevent lesions from worsening. Specific treatment modalities, such as laser therapy and vitamin A derivatives, have demonstrated some effectiveness. There has been limited evidence of the efficacy of several traditional medicines, including corticosteroids, calcineurin inhibitors, emollients, antihistamines, phototherapy, and antibiotics.
Topical Corticosteroids:
Topical corticosteroids are ineffective in most GGD cases and provide temporary relief from burning and itching without significant clinical or histological improvement. The application of topical steroids has occasionally even made symptoms worse. However, they are frequently employed as a first line of treatment in the initial stages of the illness and during diagnostic testing. Topical steroids such as betamethasone, clobetasol 17-propionate, and 0.1% triamcinolone cream are frequently used. Topical steroids may cause skin atrophy, erythema, telangiectasias, hypertrichosis, folliculitis, and striae distensae cutis.
Calcineurin Inhibitors:
Tacrolimus and Pimecrolimus are examples of calcineurin inhibitors that function at the molecular level by preventing the transcription of cytokines and the activation of T cells, which in turn controls the immunological response. Calcineurin inhibitor side effects might involve furuncles, folliculitis, dermatitis, irritation, burning, intertrigo, and itching.
UVB Phototherapy:
This involves using ultraviolet radiation, which is rarely utilized in GGD because of its limited advantages and severe side effects. The side effects can include blistering, erythema, hyperpigmentation, photoaging of the skin, an increased risk of neoplastic growth, or possibly the onset or aggravation of GGD.
Laser Therapy: This includes the use of Er: YAG laser, pulsed light (IPL), and electrofluorescence, which have been proven to be equally effective in treating GGD by eliminating diseased tissue and stimulating epidermal tissue regeneration. The benefits of the Er: YAG laser include reduced pigmentation alterations and atrophic scarring.
Systemic Corticosteroids: These include prednisone, have a wide range of effects in GGD, from partial remission to exacerbation of lesions, and are frequently administered during disease flares. Systemic corticosteroids often cause side effects such as cataracts, osteoporosis, capillary fragility, hypertension, hyperglycemia, hypokalemia, and psychological abnormalities.
Vitamin A Derivatives: Isotretinoin, acitretin, and alitretinoin, are examples of retinoids that have shown potential as systemic therapies for GGD. These retinoids control keratinocyte growth and division by attaching to the all-trans retinoid X receptor (RXR) and nuclear receptors, the all-trans retinoic acid receptor (RAR).
Antibiotics: Antibiotics, including azithromycin, erythromycin, and clarithromycin, are mostly used to treat reticulate pigmentary disorders of the skin. They have not been used frequently in GGD.
Conclusion:
GGD is still an intriguing and challenging dermatological disorder. Despite having an inflammatory acantholytic form similar to Dowling-Degos disease (DDD), there are significant clinical similarities between the two conditions that frequently result in diagnosis overlaps. Understanding and diagnosing GGD depend on knowledge of its genetic basis.
