Notalgia Paresthetica

A 50-year-old female presented with a 2-year history of pruritus on her right mid and upper back (Figure). She reported scratching her back many times a day. At times, she experienced slight pain, burning, and tingling in the area. She denied hyperalgia, throbbing, or formication. Her past health was unremarkable and there was no history of trauma to her back. There was no family history of similar problems.

Physical examination revealed a brownish lichenified patch on her right mid and upper back inferior/medial to the right scapula, corresponding to the area of pruritus. Light touch and pinprick sensations were decreased in that area. No aggravating or ameliorating factors could be identified.

Introduction. A diagnosis of notalgia (Greek, nota meaning back and algos meaning pain) paresthetica was made. The term notalgia paresthetica was coined by Astwazaturow¹ in 1934 to describe a sensory neuropathy involving the dorsal primary divisions of spinal nerves resulting in a dermopathy characterized by pruritus, pain, and paresthesia in an area of the upper back mainly between the T2 and T6 dermatomes.² 

Presentation. Typically, notalgia paresthetica presents with unilateral pruritus and/or paresthesias in a circumscribed area at the back in the T2 to T6 dermatosomal region.² The pruritus is intermittent and often paroxymal.² This may be associated with pain, paresthesia, hyperesthesia, formication, tingling, and burning sensation. Some patients may complain of loss of sensation in the affected area.³ Bilateral involvement and involvement of lower regions have also been described.^2,4 There is often a hyperpigmented patch over the affected area. The color is usually tan to brown.² The patch often has an indistinct border.² The sensation to touch, temperature, and vibration in the affected area may or may not be altered.³ 

Epidemiology. Suffice to say, notalgia paresthetica is a not uncommon condition. The exact incidence, however, is not known as many cases are not recognized or not reported. The condition is more commonly seen in Caucasians.² The female to male ratio is approximately 2 to 3:1.2,⁴ The median age of onset is around 54 to 62 years.⁴ The age of onset is much earlier in hereditary cases, especially those associated with multiple endocrine neoplasia type 2.²

Pathogenesis. It is believed that dorsal spinal nerve impingement and trauma play an important role in the pathogenesis.⁵ As the spinal nerves from T2 to T6 run a right-angle course through the spinal muscles, they are vulnerable to muscular impingement and mechanical trauma.^2,4 Muscle spasms or fibrous bands may compress the nerves and cause symptoms.⁶ The pruritus may be caused directly by the compression of unmyelinated C fibers or indirectly by mast cell degranulation secondary to substance P release.⁴ The skin hyperpigmentation may be the result of chronic rubbing and scratching.⁴ Other predisposing factors include genetic predisposition, herniated disc, degenerative disc disease, increased cutaneous innervation, prolonged bed rest, and neurotoxicity of certain chemicals.^4-6 

Histopathology. Histopathologic findings are nonspecific and include pigmentary incontinence, mild inflammatory infiltrate in the papillary dermis, and necrotic keratinocytes.^4,5 

Diagnosis and differential diagnosis. The diagnosis is a clinical one based on the history of unilateral pruritus medial or inferior to the scapula, which may be accompanied by paresthesias, pain, numbness, or hypoesthesia/hyperesthesia as well as clinical finding of localized hyperpigmentation or sensory changes in that area.⁶ Differential diagnoses include post-inflammatory hyperpigmentation, neurodermatitis, lichen simplex chronicus, fixed-drug eruption, tinea versicolor, tinea corporis, contact dermatitis, Becker’s nevus, parapsoriasis, and cutaneous amyloidosis.⁶ A skin biopsy should be considered or referral to a dermatologist if the diagnosis is in doubt to rule out other disorders. 

Prognosis. Notalgia paresthetica tends to run a chronic course. The disease is benign except those cases associated with multiple endocrine neoplasia type 2.

Treatment. Notalgia paresthetica may affect the patient’s quality of life. Treatment options include topical capsaicin, topical anesthetics, topical steroids with or without cooling agents such as menthol, intradermal injections of botulinum toxin type A, oral gabapentin, oral oxcarbazepine, spinal physiotherapy/physical therapy, transcutaneous electrical nerve/muscle stimulation, narrowband UVB, and surgical decompression of the nerve.^4,6 

Currently, no single intervention has been shown to be convincingly effective and long-lasting in the treatment of this stubborn condition. More research is needed in this area.

References: 

1. Astwazaturow M. Über paresthetiche Neuralgien und eine besondere Form derselben—Notalgia paresthetica. Dtsch Z Nervenarzt. 1934;133:188-196.

2. Raison-Peyron N, Meunier L, Acevedo M, et al. Notalgia paresthetica: clinical, physiopathological and therapeutic aspects. A study of 12 cases. J Eur Acad Dermatol Venereol. 1999;12:215-221.

3. Weber PJ, Poulos EG. Notalgia paresthetica: case reports and histologic appraisal. J Am Acad Dermatol. 1988;18:25-30.

4. Perez-Perez LC. General features and treatment of notalgia paresthetica. Skinmed. 2011;9:353-358.

5. Savk E, Savk O, Bolukbasi O, et al. Notalgia paresthetica: a study on pathogenesis. Int J Dermatol. 2000;39:754-759.

6. Ellis C. Notalgia paresthetica: the unreachable itch. Dermatol Pract Concept. 2013;3(1):2.