Acquired Idiopathic Generalized Anhidrosis.

Acquired idiopathic generalized anhidrosis is a rare condition, where the exact pathomechanism is unknown. We report a case of acquired idiopathic generalized anhidrosis in a patient who later developed lichen planus. Here an autoimmune-mediated destruction of sweat glands may be the probable pathomechanism.

What was known?

Acquired idiopathic anhidrosis is an entity of which the definite pathomechanism is unknown. Various proposed mechanisms are sudomotor dysfunction, sudomotor neuropathy, sweat gland abnormalities and occlusion of proximal duct.

Introduction

Anhidrosis is the inability to produce or deliver sweat despite appropriate thermal or pharmacological stimuli.[1] Anhidrosis can be localized or generalized. Generalized anhidrosis may occur secondary to congenital absence of sweat glands (ie, anhidrotic/hypohidrotic ectodermal dysplasia), metabolic disorders (e.g. Fabry disease), and secondary anhidrosis as a result of connective tissue disease (e.g. Sjögren syndrome), chronic dermatoses by plugging of eccrine duct (e.g., psoriasis or atopic dermatitis), panautonomic neuropathy,[2] underlying neurologic disorders with autonomic dysfunction (e.g. multiple sclerosis or Shy–Drager syndrome), peripheral neuropathies (e.g. diabetes mellitus, Guillain Barre syndrome), and drugs (e.g. anticholinergic or psychotropic agents) or it can be idiopathic.[13] We report a patient with idiopathic-acquired generalized anhidrosis that is caused due to destruction of sweat glands.

Case Report

A 47-year-old male patient presented with cutaneous burning sensation on heat exposure and absence of sweating for past 3 years. He gave history of profuse sweating in the past, which gradually decreased to a point when there was no sweating for past 3 years. He was previously working as a clerk, but for past 3 years heat intolerance prevented him from going out during day time. This resulted in marked impairment of his quality of life. He gives a history of dryness of eyes, for which ophthalmology evaluation was done and Schirmer's test was found to be negative. There was no other preexisting illness and no history of similar illness in family. Later, he developed few pruritic hyperpigmented raised lesions over his legs. Cutaneous examination showed violaceous papules and plaques in both lower limbs suggestive of lichen planus. Systemic examination showed bilateral pupils were normal, equally reacting to light, accommodation reflex and extraocular muscle function were found to be normal. There was no evidence of postural hypotension. A complete review of all the systems revealed no abnormalities.

Investigations including complete hemogram, liver and renal function test, thyroid function tests were found to be normal. Antinuclear antibody and antinuclear antibody profiles were found to be negative. Urine examination showed normal osmolarity and specific gravity. Peripheral smear, x-ray skull and bone marrow studies were done and were found to be normal. Skin biopsy from apparently normal anhidrotic skin showed the absence of eccrine sweat glands [Figures 1 and 2]. This patient was started on oral prednisolone for lichen planus, but his anhidrosis obviously showed no improvement.

Figure 1

Scanner view of section of skin showing orthokeratosis, focal thinning of epidermis. Dermis showing minimal perivascular inflammation. No eccrine glands or ducts seen.

Figure 2

High power view of dermis showing characteristic absence of sweat glands

Discussion

Acquired idiopathic generalized anhidrosis, first described by Lutembacher in 1919, is a rare condition characterized by the absence of sweating.[1] Since then, there are a few reports of the same. The typical patient is a young Japanese male, presenting with cutaneous burning sensation, heat intolerance and absence of sweating. Many patients have associated cholinergic urticaria and raised IgE levels.[3]

Various pathomechanisms proposed were idiopathic sudomotor dysfunction,[4] sudomotor neuropathy, sweat gland abnormalities and occlusion of proximal duct. The histopathology of reported cases shows marked variation, there can be normal appearing eccrine glands, eccrine gland atrophy, perieccrine lymphocytic or mast cell infiltrates, irregular arrangement of glands or occlusion of proximal duct.[5]

In our patient there was a history of profuse sweating in the past followed by generalized anhidrosis for a period of 3 years and the histopathology showed the characteristic absence of sweat glands. We explored various causes for anhidrosis, but could not find any to explain the absence of sweating. While in the course of the disease, the patient developed lesions of lichen planus. Lichen planus is an autoimmune disease and may be associated with various other autoimmune diseases. So we propose an autoimmune origin of acquired generalized anhidrosis, similar to autoimmune thyroiditis. In autoimmune thyroiditis, initially there is hyperthyroidism followed by a phase of hypothyroidism. Similarly in this case there is hypersecretion (profuse sweating) followed by the absence of sweating. This theoretically proves our hypothesis. Hence, we put forth an autoimmune-mediated destruction of eccrine sweat glands in a patient with lichen planus as a plausible hypothesis to explain the anhidrosis. These autoantibodies may be directed either against the eccrine glands itself or its nerve supply, causing a destruction leading to the absence of previously normally functioning eccrine glands.

The treatment options tried are systemic steroids, gabapentine, cyclosporine, antihistamines, with variable results.[6] In this case we gave oral prednisolone, lichen planus lesions improved, but anhidrosis didn’t show much improvement as sweat glands were absent.

What is new?

Acquired idiopathic anhidrosis occurring in association with lichen planus may be due to autoimmune destruction of eccrine glands