On further questioning during follow-up, the patient revealed that his hypertensive medication was changed from HCTZ, which he had been taking for the last 8 years, to the combination antihypertensive medication telmisartan-HCTZ before the onset of the skin eruption. Due to the temporal relationship between the new medication and onset of the eruption, the clinical impression was highly suspicious for drug-induced eruptive LP with Köbner phenomenon caused by the recent sunburn. Systemic workup for underlying causes of LP was negative. Laboratory tests revealed normal complete blood cell counts. The hepatitis panel included hepatitis A antibodies; hepatitis B surface, e antigen, and core antibodies; hepatitis B surface antigen and e antibodies; hepatitis C antibodies; and antinuclear antibodies, which were all negative.
The patient continued to develop new pruritic papules clinically consistent with LP. He was instructed to return to his primary care physician to change the telmisartan-HCTZ to a different class of antihypertensive medication. His medication was changed to atenolol. The patient also was instructed to continue the halobetasol propionate ointment 0.05% twice daily to the affected areas.
The patient returned for a follow-up visit 1 month later and reported notable improvement in pruritus and near-complete resolution of the LP after discontinuation of telmisartan-HCTZ. He also noted some degree of perifollicular repigmentation of the vitiliginous skin that had been unresponsive to prior therapy (Figure 3).
Figure 3. Four weeks after discontinuation of telmisartan-hydrochlorothiazide, the patient noted near-complete resolution of lichen planus and subtle perifollicular repigmentation on the posterior aspect of the neck (A). He exhibited marked reduction of lichen planus on the bilateral lateral arms as well as perifollicular repigmentation of vitiliginous areas (B).
Lichen planus is a pruritic and inflammatory papulosquamous skin condition that presents as scaly, flat-topped, violaceous, polygonal-shaped papules commonly involving the flexor surface of the arms and legs, oral mucosa, scalp, nails, and genitalia. Clinically, LP can present in various forms including actinic, annular, atrophic, erosive, follicular, hypertrophic, linear, pigmented, and vesicular/bullous types. Koebnerization is common, especially in the linear form of LP. There are no specific laboratory findings or serologic markers seen in LP.
The exact cause of LP remains unknown. Clinical observations and anecdotal evidence have directed the cell-mediated immune response to insulting agents such as medications or contact allergy to metals triggering an abnormal cellular immune response. Various viral agents have been reported including hepatitis C virus, human herpesvirus, herpes simplex virus, and varicella-zoster virus.1-5 Other factors such as seasonal change and the environment may contribute to the development of LP and an increase in the incidence of LP eruption has been observed from January to July throughout the United States.6 Lichen planus also has been associated with other altered immune-related disease such as ulcerative colitis, alopecia areata, vitiligo, dermatomyositis, morphea, lichen sclerosis, and myasthenia gravis.7 Increased levels of emotional stress, particularly related to family members, often is related to the onset or aggravation of symptoms.8,9
Many drug-related LP-like and lichenoid eruptions have been reported with antihypertensive drugs, antimalarial drugs, diuretics, antidepressants, nonsteroidal anti-inflammatory drugs, antimicrobial drugs, and metals. In particular, medications such as captopril, enalapril, labetalol, propranolol, chlorothiazide, HCTZ, methyldopa, chloroquine, hydroxychloroquine, quinacrine, gold salts, penicillamine, and quinidine commonly are reported to induce lichenoid drug eruption.10
Several inflammatory papulosquamous skin conditions should be considered in the differential diagnosis before confirming the diagnosis of LP. It is important to rule out lupus erythematosus, especially if the oral mucosa and scalp are involved. In addition, erosive paraneoplastic pemphigus involving primarily the oral mucosa can resemble oral LP. Nail diseases such as psoriasis, onychomycosis, and alopecia areata should be considered as the differential diagnosis of nail disease. Genital involvement also can be seen in psoriasis and lichen sclerosus.