Psoriasis is a systemic disease that affects multiple organs, usually the skin and joints, as well as the auditory, cardiovascular, and endocrine systems (J Invest Dermatol. 2013; 133(2):377). It affects around two percent of the U.S. population, and has a strong immunogenic element. Most people with psoriasis are diagnosed before the age of 40, while very few people are diagnosed later in life. The form that occurs before the age of 40 is strongly associated with the human leukocyte antigen (HLA) class I HLA-Cw6 (J Invest Dermatol. 2013). The pathogenesis of psoriasis has yet to be identified. One hypothesis is infectious Staphylococcus and Streptococcus species have been known to induce one form of psoriasis known as guttate psoriasis (J Invest Dermatol. 1997; 109: 183). The immunopathology of psoriasis begins with antigen presentation in an environment high in interferon γ (IFNγ), interleukin (IL)6, and IL1β to T-cells in draining lymph nodes, where IL12, IL23, and tumor necrosis factor (TNF) α are in high concentration. From this, TH22, TH1, and TH17 white blood cells proliferate. The pro-inflammatory T-cells return to the skin's dermal layer and release pro-inflammatory molecules that become therapeutic targets. TNFα is the most common target. Another target is the IL17 pathway, which is rather specific to auto-reactive processes (Clin Exp Immunol. 1999 Sep;117(3):580).1 These inflammatory cells cause silvery sheet-like (micaceous) scaling of the epidermis and inflammation of the skin and other systemic processes.
DIAGNOSIS OF PSORIASIS BY THE EAR
A common presentation of psoriasis is itching or tenderness with silvery micaceous scales on the posterior crease of the ear and the external auditory meatus. The hyperproliferative epidermal cells can cause buildup of scales in the external auditory canal, impaction of debris, and conductive hearing loss. On exam, the meatus and concha are red, scaly, and excoriated, with potential debris buildup (Fig. 1). Look for other signs of psoriasis, like silvery plaques on the back of the scalp (see Fig. 2 online: http://bit.ly/2RIu82G), elbows, and knees, and pitting of the nails on the hands and feet. Ask about joint pain, especially asymmetrical arthritis that involves two to four joints.
There are two manifestations of psoriasis on hearing: external ear canal inflammation and conductive loss and sensorineural hearing loss due to cochlear involvement (Fig. 3). With the hyperkeratosis and itching, patients tend to scratch or pick at their ear canals and try to clean them out. This creates a Koebner phenomenon, a hallmark of psoriasis in which the slightest trauma induces further psoriasis formation and expansion (doi.org/10.20431/2456-0022.0303003). Accumulation of scaling and skin debris causes hearing loss, increasing and decreasing edema, and swelling of the cartilaginous ear canal. The scales also make external fitting of hearing aids difficult since the diameters of the ear canal and meatus keep changing. The pressure from wearing hearing aids can also cause Koebnerization. Other Koebnerizing factors include excessive moisture in the ear canal (which commonly happens after hearing aid placement), topical sensitivity to drops or shampoos, use of instruments such as Q-tips, etc. The Koebnerization can secondarily introduce excoriations and skin breakdown that can be entry points for bacteria or fungi and possibly cause acute and chronic otitis externa.
The second manifestation of psoriasis is a topic of active research, i.e., sensorineural damage. The very inflammatory molecules that drive psoriasis, like TNFα, can induce cochlear degeneration (Auris Nasus Larynx. 2009 Feb;36(1):82). Happa, et al., presented 50 psoriatic patients who had significantly different median pure tone hearing averages than age-matched controls (J Laryngol Otol. 1997 Mar;111(3):277). However, Karabulut, et al., could not find any cochlear damage nor hearing loss in psoriatic patients (ENT Updates. 2016;6(3):140). In another study, Yen, et al., looked at 28,817 psoriatic patients and found that psoriasis is significantly associated with sudden sensorineural hearing loss (Int Adv Otol. 2010; 6:(2) 239). Vir, et al., found cochlear outer hair cell damage and high-frequency hearing loss among psoriatics compared with the control group (Am J Clin Dermatol. 2015 Jun;16(3):213). Patients with psoriatic arthritis are even more likely to have sensorineural hearing loss (Clin Exp Dermatol. 2018 Oct 2; Auris Nasus Larynx. 2016; 43:626). Borgia, et al., conducted a case-controlled study on the hearing of psoriasis patients and clarified evidence that hearing loss was more prevalent among psoriatic patients with joint disease, psoriatics who smoked, or psoriatics with the condition for over 10 years (Acta Derm Venereol. 2018; 98: 655). They also identified that psoriatics with hearing loss had a more severe case of psoriasis. Finally, they postulated that psoriatic involvement of the middle ear and potential otosclerosis may be related, though without strong evidence.
Treatment of psoriasis that involves the ears should start with an audiogram to rule out inner ear involvement. Inflammation of the ear canal can be reduced with over-the-counter (OTC) therapeutics. Only when the inflammation of the ear canal is resolved should impressions be taken for hearing aids. To prevent Koebnerization, patients with hearing aids should apply a thin layer of 1% hydrocortisone and 1% clotrimazole to the ear canal before inserting the hearing aid (Fig. 4). Alternatively, the outside of the hearing aid can be coated thinly with the two ointments. This may help prevent clogging the hearing aid with the ointment. There are many OTC topical agents that are highly effective for psoriasis (Table 1). The ear canal should not be debrided aggressively. Avoid putting potent topical steroids (like betamethasone or clobetasol) in the ear. A safe, synergistic, and more potent anti-inflammatory therapy can be formulated by combining mild- to medium-strength corticosteroids (like fluocinonlone acetonde oil otic drops) with other safer anti-inflammatory agents (e.g., topical vitamin D derivatives, like calcipotriene; or thin layers of topical calcineurin inhibitors, like cyclosporin suspension, pimecrolimus cream, tacrolimus ointment; or phosphodiesterase type 4 inhibitors, like crisaborole ointment),. Ultimately, less steroid use is better as it causes thinning of the skin. If there is cochlear involvement or the canal cannot be sufficiently treated with topical agents, then systemic agents should be considered (Table 2; doi.org/10.20431/2456-0022.0303003). The progressive sensorineural loss in psoriasis has been treated with anti-TNFα therapies or methotrexate (Acta Derm Venereol. 2018). Newer systemic therapies are promising modalities to treat sensorineural manifestations of psoriasis. In conclusion, psoriasis does affect hearing. Never aggressively debride the scales but soothe the inflammation with topical therapy when possible.