Persisting cholinergic erythema: a variant of cholinergic urticaria

Cholinergic urticaria: More than a simple inducible urticaria

BACKGROUND

Cholinergic urticaria (ChU) is characterized by small wheals induced by an elevated core temperature. Its pathomechanism and various aspects of its clinical manifestations are still poorly understood. This study aimed to evaluate the spectrum of symptoms and signs of ChU in Korean patients.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with ChU.

RESULTS

Among 203 patients (188 male and 15 female), 29 (14%) complained only of an itching or burning sensation without visible skin eruption. The prevalence of ChU was highest in patients in their twenties (56%), while most patients first developed their symptoms during their teens (65%). Patients with a visible skin eruption showed better responses to antihistamines than those without skin lesions.

CONCLUSIONS

Physicians should consider the varying manifestations of ChU, including cholinergic pruritus and erythema as minor variants, to provide better management of ChU.

Unusual urticarias

Typical urticarial lesions are transient cutaneous swellings of sudden onset, often itchy, persisting for less than 24 hours and resolving to leave normal appearing skin. Angioedema lesions are similar subcutaneous lesions. Atypical urticarias persist for longer than 24 hours, may be painful and bruised in appearance and accompanied with severe systemic symptoms. Conditions where prolonged weals are present include delayed pressure urticaria and urticarial vasculitis. These conditions do not respond well to antihistamine therapy. In delayed pressure urticaria, weals appear after a delay of hours at sites of sustained pressure on the skin and occur in association with ordinary chronic 'idiopathic' urticaria. Weals of urticarial vasculitis show histological features of venulitis, and can be accompanied by arthralgia and abdominal pain. Rarely, the condition is due to infective or autoimmune disease. Urticarial diseases, sometimes with features of urticarial vasculitis, and with associated systemic features include Schnitzler's Syndrome, Still's disease and Muckle-Wells syndrome. The latter syndrome is linked with chromosome 1q44, as is autosomal dominant cold urticaria, an unusual physical urticaria. Persistent cholinergic erythema, a variant of cholinergic urticaria, has been mistaken for a drug eruption or cutaneous mastocytosis. Rarely, food and exercise induced urticaria and anaphylaxis occur when exercise follows a specific food or any meal within a few hours. The early stages of inflammatory disease may be mistaken for urticaria and angioedema, but lesions usually persist for longer than 48 hours and are accompanied by epidermal changes.

Chronic urticaria

Chronic urticaria remains a major problem in terms of etiology, investigation, and management. It is important to identify patients in whom physical urticaria is the principal cause of disability. Once confirmed by appropriate challenge testing, no further investigation is required. Urticarial vasculitis (UV) is a major differential diagnosis of "idiopathic" urticaria (CIU). I perform biopsy of most patients in this category because UV cannot be considered confirmed in the absence of histologic evidence. Patients with confirmed UV need to be thoroughly investigated for paraproteins, lupus erythematosus hepatitis B and C, and inflammatory bowel disease. Of patients with CIU, a few (<5%) prove to have food additive reactivity confirmed by placebo-controlled challenge testing. There is no convincing evidence of the involvement of Helicobacter pylori or parasite infestation as a cause of chronic urticaria, although H pylori could have an indirect role. Recently it has become clear that 27% to 50% of patients with CIU have functional autoantibodies directed against the alpha-chain of the high-affinity IgE receptor or less commonly against IgG. These antibodies, whose involvement has now been independently confirmed in several centers, are identified by autologous serum skin testing and confirmed by histamine release studies or immunoblotting. Their removal (by intravenous Ig or plasmapheresis) or treatment by cyclosporine has proved highly beneficial in severely affected patients. However, the routine treatment of all CIU patients, irrespective of etiology, remains the judicious use of H(1) antihistamines.

Cholinergic pruritus, erythema and urticaria: a disease spectrum responding to danazol

Cholinergic pruritus and cholinergic erythema are relatively rare conditions believed to represent variants of cholinergic urticaria. We report an extremely severe and unusual case demonstrating features of both these variants before evolving into more classical cholinergic urticaria. This strongly supports the view that all three syndromes are variations of the same disease. This case demonstrated a dramatic symptomatic response to danazol which has not previously been reported.

Autonomic function in cholinergic urticaria and atopic eczema

Autonomic function in patients with cholinergic urticaria and atopic eczema was compared with that in patients with chronic idiopathic urticaria and non-atopic allergic contact dermatitis, respectively. Forty-nine patients were studied. The following specific tests of sympathetic and parasympathetic function were used to assess the integrity of autonomic control: pupillary reflex amplitude in response to pulsed light stimulation and response to topical arecoline hydrobromide (parasympathetic); the speed of pupillary dilatation following a large light reflex (sympathetic); pupillary resting diameter (sympathetic and parasympathetic); sweat gland response to forearm intradermal injection of acetylcholine chloride; and the effect of postural change and deep breathing on blood pressure and heart rate (sinus arrhythmia indicating parasympathetic function). No significant difference in autonomic function was found between the four groups of patients.